diff --git a/types/dwt/addon.pdf.d.ts b/types/dwt/addon.pdf.d.ts
new file mode 100644
index 0000000000..ef0980abfd
--- /dev/null
+++ b/types/dwt/addon.pdf.d.ts
@@ -0,0 +1,73 @@
+/*!
+* Dynamsoft WebTwain PDF Addon
+* Product: Dynamsoft Web Twain
+* Web Site: http://www.dynamsoft.com
+*
+* Copyright 2018, Dynamsoft Corporation
+* Author: Dynamsoft Support Team
+* Version: 13.4
+*/
+
+declare enum EnumDWT_ConverMode {
+    CM_DEFAULT = 0,
+    TWPT_CM_RENDERALLGRAY = 1
+}
+
+/**
+ * @class
+ */
+interface PDF {
+    /**
+     * Download and install pdf rasterizer add-on on the local system.
+     * @method Dynamsoft.WebTwain#Download
+     * @param {string} remoteFile specifies the value of which frame to get.
+     * @param {function} optionalAsyncSuccessFunc optional.
+     * The function to call when the download succeeds. Please refer to the function prototype OnSuccess.
+     * @param {function} optionalAsyncFailureFunc optional.
+     * The function to call when the download fails. Please refer to the function prototype OnFailure.
+     * @return {bool}
+     */
+    Download(remoteFile: string,
+        optionalAsyncSuccessFunc?: () => void,
+        optionalAsyncFailureFunc?: (errorCode: number, errorString: string) => void): boolean;
+
+    /**
+     *  Input the password to decrypt PDF files using PDF Rasterizer add-on.
+     * @method Dynamsoft.WebTwain#SetPassword
+     * @param {string} password Specifies the PDF password.
+     * @return {bool}
+     */
+    SetPassword(password: string): boolean;
+
+    /**
+     *  Set the image convert mode for PDF Rasterizer in Dynamic Web TWAIN.
+     * @method Dynamsoft.WebTwain#SetConvertMode
+     * @param {EnumDWT_ConverMode} convertMode Specifies the image convert mode.
+     * @return {bool}
+     */
+    SetConvertMode(convertMode: EnumDWT_ConverMode): boolean;
+
+    /**
+     *  Set the output resolution for the PDF Rasterizer in Dynamic Web TWAIN.
+     * @method Dynamsoft.WebTwain#ReadRect
+     * @param {float} fResolution Specifies the resolution for convert image from PDF file.
+     * @return {bool}
+     */
+    SetResolution(fResolution: number): boolean;
+
+    /**
+     * Judges whether the local PDF is text-based or not.
+     * @method Dynamsoft.WebTwain#ReadRect
+     * @param {string} localFile specifies the local path of the target PDF.
+     * @return {bool}
+     */
+    IsTextBasedPDF(localFile: string): boolean;
+}
+
+interface WebTwainAddon {
+    PDF: PDF;
+}
+
+interface WebTwain {
+	Addon: WebTwainAddon;
+}
diff --git a/types/dwt/dwt-tests.ts b/types/dwt/dwt-tests.ts
index 16a56f1cd2..1be94acca1 100644
--- a/types/dwt/dwt-tests.ts
+++ b/types/dwt/dwt-tests.ts
@@ -103,8 +103,8 @@ function downloadImage() {
 function loadPDF() {
     const DWObject = Dynamsoft.WebTwainEnv.GetWebTwain('dwtcontrolContainer');
     if (DWObject) {
-        DWObject.Addon.PDF.SetResolution(200);
-        DWObject.Addon.PDF.SetConvertMode(1);
+		DWObject.Addon.PDF.SetResolution(200);
+		DWObject.Addon.PDF.SetConvertMode(1);
         DWObject.IfShowFileDialog = true;
         DWObject.LoadImageEx(" ", 5);
     }
diff --git a/types/dwt/index.d.ts b/types/dwt/index.d.ts
index b19980603e..b940c6ae4e 100644
--- a/types/dwt/index.d.ts
+++ b/types/dwt/index.d.ts
@@ -1,7 +1,8 @@
-// Type definitions for dwt 13.3
+// Type definitions for dwt 13.4
 // Project: http://www.dynamsoft.com/Products/WebTWAIN_Overview.aspx
 // Definitions by: Xiao Ling <https://github.com/yushulx>
 //                 Josh Hall <https://github.com/jbh>
+//                 Lincoln Hu <https://github.com/lincoln2018>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 // TypeScript Version: 2.2
 
@@ -10,68 +11,11 @@
 * Product: Dynamsoft Web Twain
 * Web Site: http://www.dynamsoft.com
 *
-* Copyright 2017, Dynamsoft Corporation
+* Copyright 2018, Dynamsoft Corporation
 * Author: Dynamsoft Support Team
-* Version: 13.3
+* Version: 13.4
 */
 
-/**
- * Dynamsoft WebTwain Addon PDF
- */
-declare enum EnumDWT_ConverMode {
-    CM_DEFAULT = 0,
-    TWPT_CM_RENDERALLGRAY = 1
-}
-
-/**
- * @class
- */
-interface PDF {
-    /**
-     * Download and install pdf rasterizer add-on on the local system. 
-     * @method Dynamsoft.WebTwain#Download 
-     * @param {string} remoteFile specifies the value of which frame to get.
-     * @param {function} optionalAsyncSuccessFunc optional. The function to call when the download succeeds. Please refer to the function prototype OnSuccess.
-     * @param {function} optionalAsyncFailureFunc optional. The function to call when the download fails. Please refer to the function prototype OnFailure.
-     * @return {bool}
-     */
-    Download(remoteFile: string, optionalAsyncSuccessFunc?: () => void, optionalAsyncFailureFunc?: (errorCode: number, errorString: string) => void): boolean;
-
-    /**
-     *  Input the password to decrypt PDF files using PDF Rasterizer add-on. 
-     * @method Dynamsoft.WebTwain#SetPassword 
-     * @param {string} password Specifies the PDF password.
-     * @return {bool}
-     */
-    SetPassword(password: string): boolean;
-
-    /**
-     *  Set the image convert mode for PDF Rasterizer in Dynamic Web TWAIN. 
-     * @method Dynamsoft.WebTwain#SetConvertMode 
-     * @param {EnumDWT_ConverMode} convertMode Specifies the image convert mode.
-     * @return {bool}
-     */
-    SetConvertMode(convertMode: EnumDWT_ConverMode): boolean;
-
-    /**
-     *  Set the output resolution for the PDF Rasterizer in Dynamic Web TWAIN.
-     * @method Dynamsoft.WebTwain#ReadRect 
-     * @param {float} fResolution Specifies the resolution for convert image from PDF file.
-     * @return {bool}
-     */
-    SetResolution(fResolution: number): boolean;
-
-    /**
-     * Judges whether the local PDF is text-based or not.
-     * @method Dynamsoft.WebTwain#ReadRect 
-     * @param {string} localFile specifies the local path of the target PDF.
-     * @return {bool}
-     */
-    IsTextBasedPDF(localFile: string): boolean;
-}
-
-/////////////////////////////////////////////////////////////////////////////////////////////////////
-
 /**
  * @namespace Dynamsoft
  */
@@ -1318,21 +1262,11 @@ interface Container {
     Height: string | number;
 }
 
-interface WebTwainAddon {
-    PDF: PDF;
-}
-
 /**
  * @class
  */
 // properties (get/set) / sync functions
 interface WebTwain {
-    /**
-     * Returns addon.
-     * @type {WebTwainAddon}
-     */
-    Addon: WebTwainAddon;
-
     /**
      * Returns or sets whether multi-page selection is supported.
      * @type {bool}
diff --git a/types/dwt/tsconfig.json b/types/dwt/tsconfig.json
index db2ac6bbf4..13f35fcfbf 100644
--- a/types/dwt/tsconfig.json
+++ b/types/dwt/tsconfig.json
@@ -18,6 +18,7 @@
     },
     "files": [
         "index.d.ts",
+        "addon.pdf.d.ts",
         "dwt-tests.ts"
     ]
 }
\ No newline at end of file