diff --git a/README.md b/README.md
index c87a7ed1..35667030 100644
--- a/README.md
+++ b/README.md
@@ -180,7 +180,7 @@ qiniu.compressImage(file, options).then(data => {
 
   * **bucket**: 上传的目标空间
   * **file**: `File` 对象，上传的文件
-  * **key**: 文件资源名
+  * **key**: 文件资源名，为空字符串时则文件资源名也为空，为 `null` 或者 `undefined` 时则自动使用文件的 `hash` 作为文件名
   * **token**: 上传验证信息，前端通过接口请求后端获得
   * **config**: `object`，其中的每一项都为可选
 
diff --git a/package-lock.json b/package-lock.json
index d3e84c56..864d83a2 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "qiniu-js",
-  "version": "3.1.0",
+  "version": "3.1.1",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
diff --git a/package.json b/package.json
index 7a6ec13c..4c14ce06 100644
--- a/package.json
+++ b/package.json
@@ -1,7 +1,7 @@
 {
   "name": "qiniu-js",
   "jsName": "qiniu",
-  "version": "3.1.0",
+  "version": "3.1.1",
   "private": false,
   "description": "Javascript SDK for Qiniu Resource (Cloud) Storage AP",
   "main": "lib/index.js",
diff --git a/src/__tests__/utils.test.ts b/src/__tests__/utils.test.ts
new file mode 100644
index 00000000..2421c4f5
--- /dev/null
+++ b/src/__tests__/utils.test.ts
@@ -0,0 +1,8 @@
+import { createLocalKey } from '../utils'
+
+describe('api function test', () => {
+  test('createLocalKey', () => {
+    expect(createLocalKey('test', null, 1024)).toMatch('qiniu_js_sdk_upload_file_name_test_size_1024')
+    expect(createLocalKey('test', 'demo', 1024)).toMatch('qiniu_js_sdk_upload_file_name_test_key_demo_size_1024')
+  })
+})
diff --git a/src/api.ts b/src/api.ts
index 8fb8af0a..fc775815 100644
--- a/src/api.ts
+++ b/src/api.ts
@@ -43,9 +43,9 @@ export async function getUploadUrl(config: Config, token: string): Promise<strin
  * @param key 目标文件名
  * @param uploadInfo 上传信息
  */
-function getBaseUrl(bucket: string, key: string, uploadInfo: UploadInfo) {
+function getBaseUrl(bucket: string, key: string | null | undefined, uploadInfo: UploadInfo) {
   const { url, id } = uploadInfo
-  return `${url}/buckets/${bucket}/objects/${urlSafeBase64Encode(key)}/uploads/${id}`
+  return `${url}/buckets/${bucket}/objects/${key != null ? urlSafeBase64Encode(key) : '~'}/uploads/${id}`
 }
 
 export interface InitPartsData {
@@ -64,10 +64,10 @@ export interface InitPartsData {
 export function initUploadParts(
   token: string,
   bucket: string,
-  key: string,
+  key: string | null | undefined,
   uploadUrl: string
 ): utils.Response<InitPartsData> {
-  const url = `${uploadUrl}/buckets/${bucket}/objects/${urlSafeBase64Encode(key)}/uploads`
+  const url = `${uploadUrl}/buckets/${bucket}/objects/${key != null ? urlSafeBase64Encode(key) : '~'}/uploads`
   return utils.request<InitPartsData>(
     url,
     {
@@ -90,7 +90,7 @@ export interface UploadChunkData {
  */
 export function uploadChunk(
   token: string,
-  key: string,
+  key: string | null | undefined,
   index: number,
   uploadInfo: UploadInfo,
   options: Partial<utils.RequestOptions>
@@ -114,7 +114,7 @@ export type UploadCompleteData = any
  */
 export function uploadComplete(
   token: string,
-  key: string,
+  key: string | null | undefined,
   uploadInfo: UploadInfo,
   options: Partial<utils.RequestOptions>
 ): utils.Response<UploadCompleteData> {
@@ -134,7 +134,7 @@ export function uploadComplete(
  */
 export function deleteUploadedChunks(
   token: string,
-  key: string,
+  key: string | null | undefined,
   uploadinfo: UploadInfo
 ): utils.Response<void> {
   const bucket = utils.getPutPolicy(token).bucket
diff --git a/src/index.ts b/src/index.ts
index 11a4598e..298a7bbf 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -17,7 +17,7 @@ const statisticsLogger = new StatisticsLogger()
  */
 function upload(
   file: File,
-  key: string,
+  key: string | null | undefined,
   token: string,
   putExtra?: Partial<Extra>,
   config?: Partial<Config>
diff --git a/src/upload/base.ts b/src/upload/base.ts
index b608c1e3..236e342b 100644
--- a/src/upload/base.ts
+++ b/src/upload/base.ts
@@ -44,7 +44,7 @@ export interface Config {
 
 export interface UploadOptions {
   file: File
-  key: string
+  key: string | null | undefined
   token: string
   putExtra?: Partial<Extra>
   config?: Partial<Config>
@@ -88,7 +88,7 @@ export default abstract class Base {
   protected putExtra: Extra
   protected xhrList: XMLHttpRequest[] = []
   protected file: File
-  protected key: string
+  protected key: string | null | undefined
   protected aborted = false
   protected retryCount = 0
   protected token: string
diff --git a/src/utils.ts b/src/utils.ts
index e8e3cfbe..64a374fc 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -53,8 +53,9 @@ export function setLocalFileInfo(localKey: string, info: LocalInfo) {
   }
 }
 
-export function createLocalKey(name: string, key: string, size: number): string {
-  return `qiniu_js_sdk_upload_file_name_${name}_key_${key}_size_${size}`
+export function createLocalKey(name: string, key: string | null | undefined, size: number): string {
+  const localKey = key == null ? '_' : `_key_${key}_`
+  return `qiniu_js_sdk_upload_file_name_${name}${localKey}size_${size}`
 }
 
 export function removeLocalFileInfo(localKey: string) {