diff --git a/docs-src/en/README.md b/docs-src/en/README.md
index 3e798e4..4ae4407 100644
--- a/docs-src/en/README.md
+++ b/docs-src/en/README.md
@@ -820,7 +820,7 @@ Installing CA in Android could be different based on the system, we list some co
   * Settings -> Security & Location > Encryption & credentials -> Install from storage, and find your CA file to install
   * Settings -> Security -> Install from SD card, and find you CA file to install
 
-As we konw, there are several file extensions of CA file which may not recognised by all kinds of Android OS. The .crt file is the most popular, and a few systems only support .cer file such as OPPO R15. In AnyProxy, you can choose what type of file you need before installing the root CA to your devices.
+As we known, there are several file extensions of CA file which may not be recognised by all kinds of Android. The .crt file is the most popular, and a few systems only support .cer file such as OPPO R15. In AnyProxy, you can choose the type of file you need before installing the root CA to your devices.
 
 ### config iOS/Android proxy server
 
diff --git a/docs-src/en/src_doc.md b/docs-src/en/src_doc.md
index 9f5f5e3..ab017f0 100644
--- a/docs-src/en/src_doc.md
+++ b/docs-src/en/src_doc.md
@@ -621,7 +621,7 @@ Installing CA in Android could be different based on the system, we list some co
   * Settings -> Security & Location > Encryption & credentials -> Install from storage, and find your CA file to install
   * Settings -> Security -> Install from SD card, and find you CA file to install
 
-As we konw, there are several file extensions of CA file which may not recognised by all kinds of Android OS. The .crt file is the most popular, and a few systems only support .cer file such as OPPO R15. In AnyProxy, you can choose what type of file you need before installing the root CA to your devices.
+As we known, there are several file extensions of CA file which may not be recognised by all kinds of Android. The .crt file is the most popular, and a few systems only support .cer file such as OPPO R15. In AnyProxy, you can choose the type of file you need before installing the root CA to your devices.
 
 ### config iOS/Android proxy server
 
diff --git a/lib/webInterface.js b/lib/webInterface.js
index 4285728..57212e0 100644
--- a/lib/webInterface.js
+++ b/lib/webInterface.js
@@ -12,7 +12,8 @@ const express = require('express'),
   wsServer = require('./wsServer'),
   juicer = require('juicer'),
   ip = require('ip'),
-  compress = require('compression');
+  compress = require('compression'),
+  pug = require('pug');
 
 const DEFAULT_WEB_PORT = 8002; // port for web interface
 
@@ -202,6 +203,11 @@ class webInterface extends events.EventEmitter {
       }
     });
 
+    app.get('/downloadCrt', (req, res) => {
+      const pageFn = pug.compileFile(path.join(__dirname, '../resource/cert_download.pug'));
+      res.end(pageFn({ ua: req.get('user-agent') }));
+    });
+
     app.get('/fetchCrtFile', (req, res) => {
       res.setHeader('Access-Control-Allow-Origin', '*');
       const _crtFilePath = certMgr.getRootCAFilePath();
@@ -219,9 +225,8 @@ class webInterface extends events.EventEmitter {
     app.get('/api/getQrCode', (req, res) => {
       res.setHeader('Access-Control-Allow-Origin', '*');
 
-      const fileType = certFileTypes.indexOf(req.query.type) !== -1 ? req.query.type : 'crt';
       const qr = qrCode.qrcode(4, 'M');
-      const targetUrl = req.protocol + '://' + req.get('host') + '/fetchCrtFile?type=' + fileType;
+      const targetUrl = req.protocol + '://' + req.get('host') + '/downloadCrt';
       const isRootCAFileExists = certMgr.isRootCAFileExists();
 
       qr.addData(targetUrl);
diff --git a/resource/cert_download.pug b/resource/cert_download.pug
new file mode 100644
index 0000000..5c5762b
--- /dev/null
+++ b/resource/cert_download.pug
@@ -0,0 +1,91 @@
+doctype html
+html(lang="en")
+  head
+    title Download rootCA
+    meta(name='viewport', content='initial-scale=1, maximum-scale=0.5, minimum-scale=1, user-scalable=no')
+  style.
+    body {
+      color: #666;
+      line-height: 1.5;
+      font-size: 16px;
+      font-family: -apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Helvetica Neue,Helvetica,PingFang SC,Hiragino Sans GB,Microsoft YaHei,SimSun,sans-serif;
+    }
+
+    body * {
+      box-sizing: border-box;
+    }
+
+    .logo {
+      font-size: 36px;
+      margin-bottom: 40px;
+      text-align: center;
+    }
+
+    .any {
+      font-weight: 500;
+    }
+
+    .proxy {
+      font-weight: 100;
+    }
+
+    .title {
+      font-weight: bold;
+      margin: 20px 0 6px;
+    }
+
+    .button {
+      text-align: center;
+      padding: 4px 15px 5px 15px;
+      font-size: 14px;
+      font-weight: 500;
+      border-radius: 4px;
+      height: 32px;
+      margin-bottom: 10px;
+      display: block;
+      text-decoration: none;
+      border-color: #108ee9;
+      color: rgba(0, 0, 0, .65);
+      background-color: #fff;
+      border-style: solid;
+      border-width: 1px;
+      border-style: solid;
+      border-color: #d9d9d9;
+    }
+
+    .primary {
+      color: #fff;
+      background-color: #108ee9;
+      border-color: #108ee9;
+    }
+
+    .more {
+      text-align: center;
+      font-size: 14px;
+    }
+
+    .content {
+      word-break: break-all;
+      font-size: 14px;
+      line-height: 1.2;
+      margin-bottom: 10px;
+    }
+  body
+    .logo
+      span.any Any
+      span.proxy Proxy
+    .title Download:
+    .content Select a CA file to download, the .crt file is commonly used.
+    a(href="/fetchCrtFile?type=crt").button.primary rootCA.crt
+    a(href="/fetchCrtFile?type=cer").button rootCA.cer
+    .more More
+    .buttons(style='display: none')
+      a(href="/fetchCrtFile?type=pem").button rootCA.pem
+      a(href="/fetchCrtFile?type=der").button rootCA.der
+    .title User-Agent:
+    .content #{ua}
+    script(type='text/javascript').
+      window.document.querySelector('.more').addEventListener('click', function (e) {
+        e.target.style.display = 'none';
+        window.document.querySelector('.buttons').style.display = 'block';
+      });
\ No newline at end of file
diff --git a/test/spec_lib/webInterface.js b/test/spec_lib/webInterface.js
index 3eac176..1975943 100644
--- a/test/spec_lib/webInterface.js
+++ b/test/spec_lib/webInterface.js
@@ -17,26 +17,12 @@ describe('WebInterface server', () => {
     webServer.close();
   });
 
-  it('should support change CA extensions in /getQrCode', done => {
-    const certFileTypes = ['crt', 'cer', 'pem', 'der'];
-    const tasks = certFileTypes.map((type) => {
-      return directGet(`${webHost}/api/getQrCode`, { type })
-        .then(res => {
-          const body = JSON.parse(res.body);
-          expect(body.qrImgDom).toMatch('<img src="data:image/');
-          expect(body.url).toBe(`${webHost}/fetchCrtFile?type=${type}`);
-        });
-    });
-
-    Promise.all(tasks)
-      .then(done)
-      .catch(done);
-  });
-
-  it('should fallback to .crt file in /getQrCode', done => {
-    directGet(`${webHost}/api/getQrCode`, { type: 'unkonw' })
+  it('should response qrcode string in /getQrCode', done => {
+    directGet(`${webHost}/api/getQrCode`)
       .then(res => {
-        expect(JSON.parse(res.body).url).toBe(`${webHost}/fetchCrtFile?type=crt`);
+        const body = JSON.parse(res.body);
+        expect(body.qrImgDom).toMatch('<img src="data:image/');
+        expect(body.url).toBe(`${webHost}/downloadCrt`);
         done();
       })
       .catch(done);
diff --git a/web/src/component/download-root-ca.jsx b/web/src/component/download-root-ca.jsx
index ba63f57..40c1913 100644
--- a/web/src/component/download-root-ca.jsx
+++ b/web/src/component/download-root-ca.jsx
@@ -5,29 +5,26 @@
 
 import React, { PropTypes } from 'react';
 import ReactDOM from 'react-dom';
+import ClassBind from 'classnames/bind';
 import { connect } from 'react-redux';
-import { message, Button, Spin, Select } from 'antd';
+import { message, Button, Spin } from 'antd';
 import ResizablePanel from 'component/resizable-panel';
 import { hideRootCA, updateIsRootCAExists } from 'action/globalStatusAction';
 import { MenuKeyMap } from 'common/Constant';
-import { getJSON, postJSON } from 'common/ApiUtil';
+import { getJSON, ajaxGet, postJSON } from 'common/ApiUtil';
 
 import Style from './download-root-ca.less';
 import CommonStyle from '../style/common.less';
 
-const certFileTypes = ['crt', 'cer', 'pem', 'der'];
-
 class DownloadRootCA extends React.Component {
     constructor () {
         super();
         this.state = {
             loadingCAQr: false,
-            generatingCA: false,
-            fileType: certFileTypes[0]
+            generatingCA: false
         };
 
         this.onClose = this.onClose.bind(this);
-        this.onFileTypeChange = this.onFileTypeChange.bind(this);
         this.getQrCodeContent = this.getQrCodeContent.bind(this);
     }
 
@@ -41,7 +38,7 @@ class DownloadRootCA extends React.Component {
             loadingCAQr: true
         });
 
-        getJSON('/api/getQrCode', { type: this.state.fileType })
+        getJSON('/api/getQrCode')
             .then((response) => {
                 this.setState({
                     loadingCAQr: false,
@@ -60,33 +57,12 @@ class DownloadRootCA extends React.Component {
         this.props.dispatch(hideRootCA());
     }
 
-    onFileTypeChange (value) {
-        this.setState({
-            fileType: value
-        }, () => {
-            this.fetchData();
-        });
-    }
-
     getQrCodeContent () {
         const imgDomContent = { __html: this.state.CAQrCodeImageDom };
         const content = (
             <div className={Style.qrCodeWrapper} >
                 <div dangerouslySetInnerHTML={imgDomContent} />
-                <div>Scan to download rootCA.{this.state.fileType} to your Phone</div>
-                <div>You can change the CA's file extension:
-                    <Select
-                        defaultValue={this.state.fileType}
-                        className={Style.fileSelect}
-                        onChange={this.onFileTypeChange}
-                    >
-                        {
-                            certFileTypes.map(key => (
-                                <Option key={key} value={key}>{key}</Option>
-                            ))
-                        }
-                    </Select>
-                </div>
+                <span>Scan to download rootCA to your Phone</span>
             </div>
         );
 
@@ -95,6 +71,7 @@ class DownloadRootCA extends React.Component {
     }
 
     getGenerateRootCADiv () {
+
         const doToggleRemoteIntercept = () => {
             postJSON('/api/generateRootCA')
                 .then((result) => {
@@ -150,8 +127,8 @@ class DownloadRootCA extends React.Component {
                 </div>
 
                 <div className={Style.buttons} >
-                    <a href={`/fetchCrtFile?type=${this.state.fileType}`} target="_blank">
-                        <Button type="primary" size="large" >Download</Button>
+                    <a href="/fetchCrtFile" target="_blank">
+                        <Button type="primary" size="large" > Download </Button>
                     </a>
                     <span className={Style.tipSpan} >Or click the button to download.</span>
                 </div>
@@ -169,6 +146,7 @@ class DownloadRootCA extends React.Component {
         return (
             <ResizablePanel onClose={this.onClose} visible={panelVisible} >
                 {this.props.globalStatus.isRootCAFileExists ? this.getDownloadDiv() : this.getGenerateRootCADiv()}
+
             </ResizablePanel>
         );
     }
diff --git a/web/src/component/download-root-ca.less b/web/src/component/download-root-ca.less
index 550227d..8c9d1de 100644
--- a/web/src/component/download-root-ca.less
+++ b/web/src/component/download-root-ca.less
@@ -55,9 +55,4 @@
     margin-top: 18px;
     display: block;
   }
-}
-
-.fileSelect {
-  width: 60px;
-  margin-left: 8px;
 }
\ No newline at end of file