diff --git a/app/Console/Commands/AutoSchoolmate.php b/app/Console/Commands/AutoSchoolmate.php
index 2e8ba10..fa27f25 100755
--- a/app/Console/Commands/AutoSchoolmate.php
+++ b/app/Console/Commands/AutoSchoolmate.php
@@ -2,106 +2,26 @@
 
 namespace App\Console\Commands;
 
-use App\Models\Course;
-use App\Models\CourseSign;
-use App\Models\User;
+use App\Services\SchoolmateEnrollmentService;
 use Illuminate\Console\Command;
 
-
 class AutoSchoolmate extends Command
 {
-    /**
-     * The name and signature of the console command.
-     *
-     * @var string
-     */
     protected $signature = 'auto_schoolmate';
 
-    /**
-     * The console command description.
-     *
-     * @var string
-     */
-    protected $description = '已审核学员自动进入校友库';
-
-    /**
-     * Create a new command instance.
-     *
-     * @return void
-     */
-    public function __construct()
-    {
-        parent::__construct();
-    }
+    protected $description = '已审核学员自动进入校友库（含历史遗漏及开课后审核通过人员）';
 
-    /**
-     * Execute the console command.
-     *
-     * @return mixed
-     */
-    public function handle()
+    public function handle(SchoolmateEnrollmentService $service)
     {
-        // 获取所有明天开课且需要自动加入校友库的课程（只处理存在 start_date 的课程）
-        $tomorrow = date('Y-m-d', strtotime('+1 day'));
-        $courses = Course::where('auto_schoolmate', 1)
-            ->whereNotNull('start_date')
-            ->where('start_date', $tomorrow)
-            ->get();
-
-        if ($courses->isEmpty()) {
-            return $this->info('没有需要处理的课程');
-        }
-
-        $this->info("找到 {$courses->count()} 个需要处理的课程");
-
-        $totalUpdated = 0;
-        $totalSkipped = 0;
-        $processedUserIds = []; // 记录已处理的用户ID，避免重复处理
-
-        foreach ($courses as $course) {
-            // 获取报名通过的学员，并排除已经是校友的用户
-            $courseSigns = CourseSign::where('course_id', $course->id)
-                ->where('status', 1)
-                ->whereHas('user', function ($query) {
-                    // 排除已经是校友的用户（is_schoolmate = 1）
-                    $query->whereRaw('COALESCE(is_schoolmate, 0) != 1');
-                })->get();
-
-            if ($courseSigns->isEmpty()) {
-                continue;
-            }
-
-            // 获取需要更新的用户ID，并排除已经在本脚本中处理过的用户
-            $userIds = $courseSigns->pluck('user_id')
-                ->unique()
-                ->filter(function ($userId) use (&$processedUserIds) {
-                    // 如果已经处理过，跳过
-                    if (in_array($userId, $processedUserIds)) {
-                        return false;
-                    }
-                    $processedUserIds[] = $userId;
-                    return true;
-                })
-                ->values()
-                ->toArray();
-
-            if (empty($userIds)) {
-                continue;
-            }
-
-            // 批量更新：只更新还不是校友的学员；使用课程开课时间作为 schoolmate_time
-            $updated = User::batchUpdateToSchoolmate($userIds, $course->start_date);
-
-            $totalUpdated += $updated;
-            $skipped = count($userIds) - $updated;
-            $totalSkipped += $skipped;
-
-            if ($updated > 0) {
-                $this->info("课程【{$course->name}】: 更新 {$updated} 位学员，跳过 {$skipped} 位已处理学员");
-            }
-        }
-
-        return $this->info("更新完成，共处理 {$totalUpdated} 位学员，跳过 {$totalSkipped} 位已处理学员");
+        $updated = 0;
+        $service->pendingUsers($service->automaticCourses())
+            ->chunkById(200, function ($users) use ($service, &$updated) {
+                foreach ($users as $user) {
+                    $updated += $service->promote($user->id, $user->source_start_date);
+                }
+            }, 'users.id', 'id');
+
+        $this->info("自动入库完成，共补齐 {$updated} 位学员。");
+        return 0;
     }
-
 }
diff --git a/app/Console/Commands/BackfillSchoolmate.php b/app/Console/Commands/BackfillSchoolmate.php
new file mode 100644
index 0000000..cdae480
--- /dev/null
+++ b/app/Console/Commands/BackfillSchoolmate.php
@@ -0,0 +1,60 @@
+<?php
+
+namespace App\Console\Commands;
+
+use App\Models\Course;
+use App\Services\SchoolmateEnrollmentService;
+use Illuminate\Console\Command;
+
+class BackfillSchoolmate extends Command
+{
+    protected $signature = 'schoolmate:backfill
+        {course_ids : 课程ID，多个用英文逗号分隔}
+        {--execute : 正式补齐；不传时只检查并输出遗漏名单}';
+
+    protected $description = '按指定课程检查或补齐审核通过学员的校友资格';
+
+    public function handle(SchoolmateEnrollmentService $service)
+    {
+        $raw = (string) $this->argument('course_ids');
+        if (!preg_match('/^[1-9][0-9]*(,[1-9][0-9]*)*$/D', $raw)) {
+            $this->error('课程ID必须为正整数，多个用英文逗号分隔。');
+            return 1;
+        }
+        $ids = array_values(array_unique(explode(',', $raw)));
+        $courses = Course::whereIn('id', $ids);
+        $found = (clone $courses)->get(['id', 'name', 'start_date']);
+        $missingIds = array_diff($ids, $found->pluck('id')->all());
+        if ($missingIds) {
+            $this->error('课程不存在或已删除：' . implode(',', $missingIds));
+            return 1;
+        }
+        // 缺少开课日期时无法确定历史入库时间，整批停止，避免只补一部分。
+        foreach ($found as $course) {
+            if (!$course->start_date) {
+                $this->error("课程 {$course->id}【{$course->name}】缺少开课日期，请先补全。");
+                return 1;
+            }
+        }
+        $this->table(['课程ID', '课程名称', '开课日期'], $found->map(function ($course) {
+            return [$course->id, $course->name, $course->start_date];
+        })->all());
+        $execute = (bool) $this->option('execute');
+        $this->info($execute ? '正式执行：仅补齐尚非校友的审核通过学员。' : '检查模式：不会修改任何学员数据。');
+        $total = 0;
+        $updated = 0;
+        $service->pendingUsers($courses)->chunkById(200, function ($users) use ($service, $execute, &$total, &$updated) {
+            $rows = [];
+            foreach ($users as $user) {
+                $total++;
+                $rows[] = [$user->id, $user->name, $user->mobile, $user->source_start_date];
+                if ($execute) {
+                    $updated += $service->promote($user->id, $user->source_start_date);
+                }
+            }
+            $this->table(['学员ID', '姓名', '手机号', '拟入库日期（所选课程最早开课日）'], $rows);
+        }, 'users.id', 'id');
+        $this->info("发现遗漏 {$total} 人" . ($execute ? "，实际补齐 {$updated} 人。" : '；正式补齐请追加 --execute。'));
+        return 0;
+    }
+}
diff --git a/app/Services/SchoolmateEnrollmentService.php b/app/Services/SchoolmateEnrollmentService.php
new file mode 100644
index 0000000..2f57540
--- /dev/null
+++ b/app/Services/SchoolmateEnrollmentService.php
@@ -0,0 +1,55 @@
+<?php
+
+namespace App\Services;
+
+use App\Models\Course;
+use App\Models\CourseSign;
+use App\Models\User;
+use Illuminate\Support\Facades\DB;
+
+class SchoolmateEnrollmentService
+{
+    /**
+     * 仅选择未删除、尚未成为校友且有有效审核通过报名的学员。
+     * 多门课程取最早开课日期；指定课程补齐不受自动入库开关限制。
+     */
+    public function pendingUsers($courses)
+    {
+        $sources = CourseSign::query()
+            ->join('courses', 'courses.id', '=', 'course_signs.course_id')
+            ->whereNull('courses.deleted_at')
+            ->whereIn('courses.id', (clone $courses)->select('courses.id'))
+            ->where('course_signs.status', 1)
+            ->select('course_signs.user_id')
+            ->selectRaw('MIN(courses.start_date) as source_start_date')
+            ->groupBy('course_signs.user_id');
+
+        return User::query()
+            ->joinSub($sources, 'schoolmate_sources', function ($join) {
+                $join->on('users.id', '=', 'schoolmate_sources.user_id');
+            })
+            ->whereRaw('COALESCE(users.is_schoolmate, 0) != 1')
+            ->select('users.*', 'schoolmate_sources.source_start_date');
+    }
+
+    public function automaticCourses()
+    {
+        // 保留开课前一天入库的原行为，同时补查历史及开课后审核通过的学员。
+        return Course::where('auto_schoolmate', 1)
+            ->whereNotNull('start_date')
+            ->whereDate('start_date', '<=', now()->addDay()->toDateString());
+    }
+
+    public function promote(int $userId, string $startDate): int
+    {
+        return DB::transaction(function () use ($userId, $startDate) {
+            // 手工补齐和自动任务同时运行时，不覆盖已有校友的入库时间。
+            $user = User::whereKey($userId)->lockForUpdate()->first();
+            if (!$user || $user->is_schoolmate == 1) {
+                return 0;
+            }
+
+            return User::batchUpdateToSchoolmate([$userId], $startDate);
+        });
+    }
+}
diff --git a/tests/Feature/SchoolmateEnrollmentCommandTest.php b/tests/Feature/SchoolmateEnrollmentCommandTest.php
new file mode 100644
index 0000000..bae7e75
--- /dev/null
+++ b/tests/Feature/SchoolmateEnrollmentCommandTest.php
@@ -0,0 +1,121 @@
+<?php
+
+namespace Tests\Feature;
+
+use App\Models\User;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Carbon;
+use Illuminate\Support\Facades\DB;
+use Illuminate\Support\Facades\Schema;
+use Tests\TestCase;
+
+class SchoolmateEnrollmentCommandTest extends TestCase
+{
+    protected function setUp(): void
+    {
+        parent::setUp();
+        config(['database.default' => 'sqlite', 'database.connections.sqlite.database' => ':memory:', 'audit.enabled' => false]);
+        DB::purge('sqlite');
+        Carbon::setTestNow('2026-10-15 10:00:00');
+        Schema::create('users', function (Blueprint $table) {
+            $table->id();
+            $table->string('name')->default('测试学员');
+            $table->string('mobile')->nullable();
+            $table->integer('is_schoolmate')->nullable();
+            $table->dateTime('schoolmate_time')->nullable();
+            $table->timestamps();
+            $table->softDeletes();
+        });
+        Schema::create('courses', function (Blueprint $table) {
+            $table->id();
+            $table->string('name')->default('测试课程');
+            $table->date('start_date')->nullable();
+            $table->integer('auto_schoolmate')->default(0);
+            $table->softDeletes();
+        });
+        Schema::create('course_signs', function (Blueprint $table) {
+            $table->id();
+            $table->integer('course_id');
+            $table->integer('user_id');
+            $table->integer('status')->default(1);
+            $table->softDeletes();
+        });
+    }
+
+    protected function tearDown(): void
+    {
+        Carbon::setTestNow();
+        parent::tearDown();
+    }
+
+    private function course(int $id, ?string $date, int $auto = 0): void
+    {
+        DB::table('courses')->insert(['id' => $id, 'start_date' => $date, 'auto_schoolmate' => $auto]);
+    }
+
+    private function sign(int $userId, int $courseId, int $status = 1, ?string $deleted = null): void
+    {
+        DB::table('course_signs')->insert(['user_id' => $userId, 'course_id' => $courseId, 'status' => $status, 'deleted_at' => $deleted]);
+    }
+
+    public function test_preview_does_not_write_and_execute_is_idempotent_and_preserves_existing_schoolmates(): void
+    {
+        $this->course(1, '2025-06-01');
+        $this->course(2, '2024-03-01');
+        DB::table('users')->insert([
+            ['id' => 1, 'is_schoolmate' => null, 'schoolmate_time' => null, 'deleted_at' => null],
+            ['id' => 2, 'is_schoolmate' => 1, 'schoolmate_time' => '2020-01-01 00:00:00', 'deleted_at' => null],
+            ['id' => 3, 'is_schoolmate' => 0, 'schoolmate_time' => null, 'deleted_at' => '2025-01-01 00:00:00'],
+            ['id' => 4, 'is_schoolmate' => 0, 'schoolmate_time' => null, 'deleted_at' => null],
+            ['id' => 5, 'is_schoolmate' => 0, 'schoolmate_time' => null, 'deleted_at' => null],
+        ]);
+        foreach ([1, 2, 3] as $id) $this->sign($id, 1);
+        $this->sign(1, 2);
+        $this->sign(1, 2); // 同人重复报名只补一次
+        $this->sign(4, 1, 0);
+        $this->sign(5, 1, 1, '2025-01-01 00:00:00');
+        $this->artisan('schoolmate:backfill', ['course_ids' => '1,2'])->expectsOutputToContain('发现遗漏 1 人')->assertExitCode(0);
+        $this->assertNull(DB::table('users')->where('id', 1)->value('is_schoolmate'));
+        User::withoutEvents(function () {
+            $this->artisan('schoolmate:backfill', ['course_ids' => '1,2', '--execute' => true])->expectsOutputToContain('实际补齐 1 人')->assertExitCode(0);
+        });
+        $this->assertSame('2024-03-01 00:00:00', DB::table('users')->where('id', 1)->value('schoolmate_time'));
+        $this->assertSame('2020-01-01 00:00:00', DB::table('users')->where('id', 2)->value('schoolmate_time'));
+        foreach ([3, 4, 5] as $id) $this->assertEquals(0, DB::table('users')->where('id', $id)->value('is_schoolmate'));
+        $this->artisan('schoolmate:backfill', ['course_ids' => '1,2', '--execute' => true])->expectsOutputToContain('实际补齐 0 人')->assertExitCode(0);
+    }
+
+    public function test_automatic_enrollment_catches_history_and_late_approval_but_respects_course_switch_and_date(): void
+    {
+        $this->course(1, '2024-01-01', 1);
+        $this->course(2, '2026-10-16', 1);
+        $this->course(3, '2026-10-17', 1);
+        $this->course(4, '2024-01-01', 0);
+        foreach ([1, 2, 3, 4, 5] as $id) {
+            DB::table('users')->insert(['id' => $id, 'is_schoolmate' => 0]);
+            $this->sign($id, min($id, 4), $id === 5 ? 0 : 1);
+        }
+        User::withoutEvents(function () {
+            $this->artisan('auto_schoolmate')->expectsOutputToContain('共补齐 2 位')->assertExitCode(0);
+            // 开课后才通过审核的历史课程报名，下次任务仍能处理。
+            $this->sign(5, 1);
+            $this->artisan('auto_schoolmate')->expectsOutputToContain('共补齐 1 位')->assertExitCode(0);
+        });
+        foreach ([1, 2, 5] as $id) $this->assertEquals(1, DB::table('users')->where('id', $id)->value('is_schoolmate'));
+        foreach ([3, 4] as $id) $this->assertEquals(0, DB::table('users')->where('id', $id)->value('is_schoolmate'));
+    }
+
+    public function test_invalid_missing_deleted_or_undated_courses_abort_without_partial_updates(): void
+    {
+        $this->course(1, '2024-01-01');
+        $this->course(2, null);
+        $this->course(3, '2024-01-01');
+        DB::table('courses')->where('id', 3)->update(['deleted_at' => '2025-01-01']);
+        DB::table('users')->insert(['id' => 1, 'is_schoolmate' => 0]);
+        $this->sign(1, 1);
+        foreach (['1,0', '1,999', '1,2', '1,3'] as $ids) {
+            $this->artisan('schoolmate:backfill', ['course_ids' => $ids, '--execute' => true])->assertExitCode(1);
+        }
+        $this->assertEquals(0, DB::table('users')->where('id', 1)->value('is_schoolmate'));
+    }
+}