diff --git a/app/Models/Member.php b/app/Models/Member.php
index ca596a6..a81e678 100644
--- a/app/Models/Member.php
+++ b/app/Models/Member.php
@@ -30,6 +30,10 @@ class Member extends Model
     const DISABILITY_STATUS_APPROVED = 'approved';
     const DISABILITY_STATUS_REJECTED = 'rejected';
 
+    // Identity type constants (病友/家長)
+    const IDENTITY_PATIENT = 'patient';   // 病友
+    const IDENTITY_PARENT = 'parent';     // 家長/父母
+
     protected $fillable = [
         'user_id',
         'full_name',
@@ -47,6 +51,8 @@ class Member extends Model
         'membership_expires_at',
         'membership_status',
         'membership_type',
+        'identity_type',
+        'guardian_member_id',
         'disability_certificate_path',
         'disability_certificate_status',
         'disability_verified_by',
@@ -72,6 +78,50 @@ class Member extends Model
         return $this->hasMany(MembershipPayment::class);
     }
 
+    /**
+     * 監護人（父母）
+     */
+    public function guardian()
+    {
+        return $this->belongsTo(Member::class, 'guardian_member_id');
+    }
+
+    /**
+     * 被監護人（子女）
+     */
+    public function dependents()
+    {
+        return $this->hasMany(Member::class, 'guardian_member_id');
+    }
+
+    /**
+     * 是否為病友
+     */
+    public function isPatient(): bool
+    {
+        return $this->identity_type === self::IDENTITY_PATIENT;
+    }
+
+    /**
+     * 是否為家長/父母
+     */
+    public function isParent(): bool
+    {
+        return $this->identity_type === self::IDENTITY_PARENT;
+    }
+
+    /**
+     * 取得身份類型標籤
+     */
+    public function getIdentityTypeLabelAttribute(): string
+    {
+        return match ($this->identity_type) {
+            self::IDENTITY_PATIENT => '病友',
+            self::IDENTITY_PARENT => '家長/父母',
+            default => '未設定',
+        };
+    }
+
     /**
      * 關聯的收入記錄
      */
diff --git a/database/migrations/2026_01_25_043205_add_identity_and_guardian_to_members_table.php b/database/migrations/2026_01_25_043205_add_identity_and_guardian_to_members_table.php
new file mode 100644
index 0000000..8bd44a2
--- /dev/null
+++ b/database/migrations/2026_01_25_043205_add_identity_and_guardian_to_members_table.php
@@ -0,0 +1,36 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    /**
+     * Run the migrations.
+     *
+     * Adds identity_type (病友/家長) and guardian relationship fields.
+     */
+    public function up(): void
+    {
+        Schema::table('members', function (Blueprint $table) {
+            // 身份類型：病友 or 家長/父母
+            $table->string('identity_type')->nullable()->after('membership_type');
+
+            // 監護人關係（未成年人指向其父母的 member_id）
+            $table->foreignId('guardian_member_id')->nullable()->after('identity_type')
+                ->constrained('members')->nullOnDelete();
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        Schema::table('members', function (Blueprint $table) {
+            $table->dropForeign(['guardian_member_id']);
+            $table->dropColumn(['identity_type', 'guardian_member_id']);
+        });
+    }
+};