diff --git a/README.md b/README.md
index 2f229cb..01ff1e1 100644
--- a/README.md
+++ b/README.md
@@ -46,10 +46,10 @@ exports.cos = {
 // {app_root}/config/config.default.js
 exports.cos = {
   client: {
-    secretId: '',
-    secretKey: '',
-    bucket: '',
-    region: '',
+    SecretId: '',
+    SecretKey: '',
+    Bucket: '',
+    Region: '',
   }
 };
 ```
@@ -62,6 +62,88 @@ exports.cos = {
 };
 ```
 
+## Usage
+
+You can aquire tencent cloud cos instance on `app` or `ctx`.
+// upload a file in controller
+
+- File Mode：The file is temporarily stored as cache in your server during the process;
+
+```js
+const path = require('path');
+const Controller = require('egg').Controller;
+
+module.exports = class extends Controller {
+  async upload() {
+    const ctx = this.ctx;
+    // please enable `file` mode of `egg-multipart`.
+    const file = ctx.request.files[0];
+    const name = 'egg-cos/' + path.basename(file.filename);
+    let result;
+    try {
+      result = await ctx.cos.put(name, file.filepath);
+    } finally {
+      // need to remove the tmp files
+      await ctx.cleanupRequestFiles();
+    }
+
+    if (result) {
+      ctx.logger.info('cos response:\n', result);
+      ctx.body = {
+        url: `https://${result.Location}`
+      };
+    } else {
+      ctx.body = 'please select a file to upload！';
+    }
+  }
+};
+```
+- upload by Stream：The file is transfered to cloud server directly, not go through your server;
+
+```js
+const Controller = require('egg').Controller;
+const sendToWormhole = require('stream-wormhole');
+async upload() {
+  const ctx = this.ctx;
+  const parts = ctx.multipart();
+  let part,results=[];
+  while ((part = await parts()) != null) {
+      if (part.length) {
+          // This is content of part stream
+          console.log('field: ' + part[0]);
+          console.log('value: ' + part[1]);
+          console.log('valueTruncated: ' + part[2]);
+          console.log('fieldnameTruncated: ' + part[3]);
+      } else {
+          if (!part.filename) {
+              return;
+          }
+          console.log('field: ' + part.fieldname);
+          console.log('filename: ' + part.filename);
+          console.log('encoding: ' + part.encoding);
+          console.log('mime: ' + part.mime);
+          console.log("part",part.stream,typeof part);
+          // file processing, uploading the file to Tencent Cloud Server
+          let result;
+          let path=await ctx.helper.MD5encode(String(Date.now()));
+          let typeArray=part.mime.split('/');
+          let type=typeArray[typeArray.length-1];
+          let name='ysxbdms/projects/'+path+`.${type}`;//the upload links
+          try {
+              result = await ctx.cos.putStream(name,part);
+          } catch (err) {
+              await sendToWormhole(part);
+              throw err;
+          }
+          console.log(result);
+          results.push(result);
+      }
+  }
+  console.log('and we are done parsing the form!');
+  ctx.body=results;
+};
+```
+
 ## Questions & Suggestions
 
 Please open an issue [here](https://github.com/romoo/egg-cos/issues).
diff --git a/app/extend/context.js b/app/extend/context.js
new file mode 100644
index 0000000..ac042bc
--- /dev/null
+++ b/app/extend/context.js
@@ -0,0 +1,7 @@
+'use strict';
+
+module.exports = {
+  get cos() {
+    return this.app.cos;
+  },
+};
diff --git a/lib/cos.js b/lib/cos.js
index 197e32f..2821a7f 100644
--- a/lib/cos.js
+++ b/lib/cos.js
@@ -1,15 +1,62 @@
 'use strict';
 
 const assert = require('assert');
-const COS = require('cos-nodejs-sdk-v5');
+const COS_NODEJS_SDK = require('cos-nodejs-sdk-v5');
+
+class COS extends COS_NODEJS_SDK {
+  constructor(options) {
+    super(options);
+    this.Bucket = options.Bucket || '';
+    this.Region = options.Region || '';
+  }
+
+  /**
+   * 上传本地文件到COS文件储存桶
+   * @param {String} Key 设定上传到cos的路径
+   * @param {String} FilePath 本地需要上传的文件
+   * @param {Object} options 设定Bucket存储桶和Region区域的选项
+   * @return {Promise<Object>} Promise包裹的data
+   */
+  put(Key, FilePath, options = {}) {
+    const Bucket = options.Bucket || this.Bucket;
+    const Region = options.Region || this.Region;
+    return new Promise((s, j) => {
+      this.sliceUploadFile({ Bucket, Region, Key, FilePath }, (err, data) => {
+        err ? j(JSON.stringify(err)) : s(data);
+      });
+    });
+  }
+
+  /**
+   * stream 模式上传文件，不用在服务器缓存
+   * @param {String} Key 设定上传到cos的路径
+   * @param {Object} Body 本地需要上传的文件流
+   * @param {Object} options 设定Bucket存储桶和Region区域的选项
+   * @return {Promise<Object>} Promise包裹的data
+   */
+  putStream(Key, Body, options = {}) {
+    const Bucket = options.Bucket || this.Bucket;
+    const Region = options.Region || this.Region;
+    return new Promise((s, j) => {
+      this.putObject({ Bucket, Region, Key, Body }, (err, data) => {
+        err ? j(JSON.stringify(err)) : s(data);
+      });
+    });
+  }
+}
 
 const createOneClient = (config, app) => {
-  assert(config.secretId && config.secretKey, '[egg-cos] secretId secretKey is required on config');
-  app.coreLogger.info('[egg-cos] init %s', config.secretId);
+  assert(
+    config.SecretId && config.SecretKey,
+    '[egg-cos] `SecretId` `SecretKey` is required on config'
+  );
+  app.coreLogger.info('[egg-cos] init %s', config.SecretId);
 
   return new COS({
-    SecretId: config.secretId,
-    SecretKey: config.secretKey,
+    SecretId: config.SecretId,
+    SecretKey: config.SecretKey,
+    Bucket: config.Bucket,
+    Region: config.Region,
   });
 };
 
diff --git a/package.json b/package.json
index 4f29415..a1862e4 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "egg-cos",
-  "version": "1.0.3",
+  "version": "2.0.0",
   "description": "tencent cloud cos plugin for egg",
   "eggPlugin": {
     "name": "cos"