diff --git a/packages/services/file-service/src/adapters/outbound/persistence/file-postgres.repository.ts b/packages/services/file-service/src/adapters/outbound/persistence/file-postgres.repository.ts
index 5e30ea1..f0158a8 100644
--- a/packages/services/file-service/src/adapters/outbound/persistence/file-postgres.repository.ts
+++ b/packages/services/file-service/src/adapters/outbound/persistence/file-postgres.repository.ts
@@ -93,6 +93,7 @@ export class FilePostgresRepository
   private toEntity(orm: FileORM): FileEntity {
     return FileEntity.fromPersistence({
       id: orm.id,
+      tenantId: orm.tenantId,
       userId: orm.userId,
       conversationId: orm.conversationId,
       originalName: orm.originalName,
diff --git a/packages/services/file-service/src/domain/entities/file.entity.ts b/packages/services/file-service/src/domain/entities/file.entity.ts
index 83ec120..4de4b70 100644
--- a/packages/services/file-service/src/domain/entities/file.entity.ts
+++ b/packages/services/file-service/src/domain/entities/file.entity.ts
@@ -19,6 +19,7 @@ export enum FileStatus {
  */
 export class FileEntity {
   readonly id: string;
+  readonly tenantId: string;
   readonly userId: string;
   conversationId: string | null;
   originalName: string;
@@ -37,6 +38,7 @@ export class FileEntity {
 
   private constructor(props: {
     id: string;
+    tenantId: string;
     userId: string;
     conversationId: string | null;
     originalName: string;
@@ -58,6 +60,7 @@ export class FileEntity {
 
   static create(props: {
     id: string;
+    tenantId?: string;
     userId: string;
     conversationId?: string;
     originalName: string;
@@ -70,6 +73,7 @@ export class FileEntity {
     const now = new Date();
     return new FileEntity({
       id: props.id,
+      tenantId: props.tenantId || '',
       userId: props.userId,
       conversationId: props.conversationId || null,
       originalName: props.originalName,
@@ -90,6 +94,7 @@ export class FileEntity {
 
   static fromPersistence(props: {
     id: string;
+    tenantId: string;
     userId: string;
     conversationId: string | null;
     originalName: string;
diff --git a/scripts/migrations/20260207_add_tenant_id_to_files.sql b/scripts/migrations/20260207_add_tenant_id_to_files.sql
new file mode 100644
index 0000000..b77c523
--- /dev/null
+++ b/scripts/migrations/20260207_add_tenant_id_to_files.sql
@@ -0,0 +1,46 @@
+-- ===========================================
+-- 迁移: file-service files 表添加 tenant_id
+-- 日期: 2026-02-07
+-- ===========================================
+
+-- 默认租户 ID
+DO $$
+DECLARE
+  default_tenant UUID := '00000000-0000-0000-0000-000000000001';
+BEGIN
+  -- 1. 添加 tenant_id 列（如果不存在）
+  IF NOT EXISTS (
+    SELECT 1 FROM information_schema.columns
+    WHERE table_name = 'files' AND column_name = 'tenant_id'
+  ) THEN
+    ALTER TABLE files ADD COLUMN tenant_id UUID NOT NULL DEFAULT default_tenant;
+    RAISE NOTICE 'Added tenant_id column to files table';
+  ELSE
+    RAISE NOTICE 'tenant_id column already exists in files table';
+  END IF;
+
+  -- 2. 回填现有记录
+  UPDATE files SET tenant_id = default_tenant WHERE tenant_id IS NULL;
+
+  -- 3. 创建索引（如果不存在）
+  IF NOT EXISTS (
+    SELECT 1 FROM pg_indexes WHERE indexname = 'idx_files_tenant_id'
+  ) THEN
+    CREATE INDEX idx_files_tenant_id ON files(tenant_id);
+    RAISE NOTICE 'Created index idx_files_tenant_id';
+  END IF;
+
+  IF NOT EXISTS (
+    SELECT 1 FROM pg_indexes WHERE indexname = 'idx_files_tenant'
+  ) THEN
+    CREATE INDEX idx_files_tenant ON files(tenant_id);
+    RAISE NOTICE 'Created index idx_files_tenant';
+  END IF;
+
+  IF NOT EXISTS (
+    SELECT 1 FROM pg_indexes WHERE indexname = 'idx_files_tenant_user'
+  ) THEN
+    CREATE INDEX idx_files_tenant_user ON files(tenant_id, user_id);
+    RAISE NOTICE 'Created index idx_files_tenant_user';
+  END IF;
+END $$;