diff --git a/apps/api/app/dependencies.py b/apps/api/app/dependencies.py
index 4c86d76c3..98f772407 100644
--- a/apps/api/app/dependencies.py
+++ b/apps/api/app/dependencies.py
@@ -91,7 +91,13 @@ class DependencyContainer:
     @property
     def workspace_invitation_repository(self):
         if self._workspace_invitation_repository is None:
-            self._workspace_invitation_repository = InMemoryWorkspaceInvitationRepository()
+            from apps.api.app.config import settings
+            if settings.USE_IN_MEMORY_DB:
+                from packages.adapters.in_memory.workspace_invitation_repository import InMemoryWorkspaceInvitationRepository
+                self._workspace_invitation_repository = InMemoryWorkspaceInvitationRepository()
+            else:
+                from packages.adapters.postgres.workspace_invitation_repository import PostgresWorkspaceInvitationRepository
+                self._workspace_invitation_repository = PostgresWorkspaceInvitationRepository(settings.DATABASE_URL)
         return self._workspace_invitation_repository
     
     @property
diff --git a/packages/adapters/postgres/__init__.py b/packages/adapters/postgres/__init__.py
index 598c1f8dd..e67abd8ab 100644
--- a/packages/adapters/postgres/__init__.py
+++ b/packages/adapters/postgres/__init__.py
@@ -4,9 +4,11 @@ PostgreSQL 适配器
 from packages.adapters.postgres.user_repository import PostgresUserRepository
 from packages.adapters.postgres.workspace_repository import PostgresWorkspaceRepository
 from packages.adapters.postgres.workspace_member_repository import PostgresWorkspaceMemberRepository
+from packages.adapters.postgres.workspace_invitation_repository import PostgresWorkspaceInvitationRepository
 
 __all__ = [
     "PostgresUserRepository",
     "PostgresWorkspaceRepository",
     "PostgresWorkspaceMemberRepository",
+    "PostgresWorkspaceInvitationRepository",
 ]
diff --git a/packages/adapters/postgres/workspace_invitation_repository.py b/packages/adapters/postgres/workspace_invitation_repository.py
new file mode 100644
index 000000000..188c300bf
--- /dev/null
+++ b/packages/adapters/postgres/workspace_invitation_repository.py
@@ -0,0 +1,126 @@
+"""
+PostgreSQL WorkspaceInvitation Repository 实现
+"""
+from typing import Optional, List
+import psycopg2
+from psycopg2.extras import RealDictCursor
+
+from packages.domain.entities import WorkspaceInvitation
+from packages.ports.workspace_invitation_repository import WorkspaceInvitationRepository
+
+
+class PostgresWorkspaceInvitationRepository(WorkspaceInvitationRepository):
+    """WorkspaceInvitation 仓储 PostgreSQL 实现"""
+    
+    def __init__(self, connection_string: str):
+        self.connection_string = connection_string
+    
+    def _get_connection(self):
+        return psycopg2.connect(self.connection_string, cursor_factory=RealDictCursor)
+    
+    def save(self, invitation: WorkspaceInvitation) -> None:
+        """保存邀请"""
+        conn = self._get_connection()
+        try:
+            with conn.cursor() as cur:
+                cur.execute("""
+                    INSERT INTO workspace_invitations (
+                        id, workspace_id, email, role, token,
+                        invited_by, expires_at, status, created_at
+                    ) VALUES (
+                        %(id)s, %(workspace_id)s, %(email)s, %(role)s, %(token)s,
+                        %(invited_by)s, %(expires_at)s, %(status)s, %(created_at)s
+                    )
+                    ON CONFLICT (id) DO UPDATE SET
+                        status = EXCLUDED.status
+                """, {
+                    "id": invitation.id,
+                    "workspace_id": invitation.workspace_id,
+                    "email": invitation.email,
+                    "role": invitation.role,
+                    "token": invitation.token,
+                    "invited_by": invitation.invited_by,
+                    "expires_at": invitation.expires_at,
+                    "status": invitation.status,
+                    "created_at": invitation.created_at,
+                })
+            conn.commit()
+        finally:
+            conn.close()
+    
+    def find_by_id(self, invitation_id: str) -> Optional[WorkspaceInvitation]:
+        """根据 ID 查找邀请"""
+        conn = self._get_connection()
+        try:
+            with conn.cursor() as cur:
+                cur.execute("SELECT * FROM workspace_invitations WHERE id = %s", (invitation_id,))
+                row = cur.fetchone()
+                return self._row_to_invitation(row) if row else None
+        finally:
+            conn.close()
+    
+    def find_by_token(self, token: str) -> Optional[WorkspaceInvitation]:
+        """根据 token 查找邀请"""
+        conn = self._get_connection()
+        try:
+            with conn.cursor() as cur:
+                cur.execute("SELECT * FROM workspace_invitations WHERE token = %s", (token,))
+                row = cur.fetchone()
+                return self._row_to_invitation(row) if row else None
+        finally:
+            conn.close()
+    
+    def find_by_email(self, email: str) -> List[WorkspaceInvitation]:
+        """根据邮箱查找所有邀请"""
+        conn = self._get_connection()
+        try:
+            with conn.cursor() as cur:
+                cur.execute(
+                    "SELECT * FROM workspace_invitations WHERE email = %s ORDER BY created_at DESC",
+                    (email,)
+                )
+                rows = cur.fetchall()
+                return [self._row_to_invitation(row) for row in rows]
+        finally:
+            conn.close()
+    
+    def find_pending_by_email(self, email: str) -> List[WorkspaceInvitation]:
+        """查找邮箱的待处理邀请"""
+        conn = self._get_connection()
+        try:
+            with conn.cursor() as cur:
+                cur.execute("""
+                    SELECT * FROM workspace_invitations 
+                    WHERE email = %s AND status = 'pending' AND expires_at > NOW()
+                    ORDER BY created_at DESC
+                """, (email,))
+                rows = cur.fetchall()
+                return [self._row_to_invitation(row) for row in rows]
+        finally:
+            conn.close()
+    
+    def delete(self, invitation_id: str) -> bool:
+        """删除邀请"""
+        conn = self._get_connection()
+        try:
+            with conn.cursor() as cur:
+                cur.execute("DELETE FROM workspace_invitations WHERE id = %s", (invitation_id,))
+                deleted = cur.rowcount > 0
+            conn.commit()
+            return deleted
+        finally:
+            conn.close()
+    
+    def _row_to_invitation(self, row: dict) -> WorkspaceInvitation:
+        """将数据库行转换为 WorkspaceInvitation 对象"""
+        return WorkspaceInvitation(
+            id=row["id"],
+            workspace_id=row["workspace_id"],
+            email=row["email"],
+            role=row["role"],
+            token=row["token"],
+            invited_by=row["invited_by"],
+            expires_at=row["expires_at"],
+            status=row["status"],
+            created_at=row["created_at"],
+        )