来自:http://www.houkai.com/blog/6010.html

在Qt助手（assistant.exe）搜索关键字”Setting the Application Icon”就可以看到在各种平台设置Qt程序图标的方法。

Setting the Application Icon on Windows

First, create an ICO format bitmap file that contains the icon image. This can be done with e.g. Microsoft Visual C++: Select File|New, then select the File tab in the dialog that appears, and choose Icon. (Note that you do not need to load your application into Visual C++; here we are only using the icon editor.)

Store the ICO file in your application’s source code directory, for example, with the name myappico.ico. Then, create a text file called, say, myapp.rc in which you put a single line of text:

IDI_ICON1               ICON    DISCARDABLE     "myappico.ico"Finally, assuming you are using qmake to generate your makefiles, add this line to your myapp.pro file:

RC_FILE = myapp.rcRegenerate your makefile and your application. The .exe file will now be represented with your icon in Explorer.

If you do not use qmake, the necessary steps are: first, run the rc program on the .rc file, then link your application with the resulting .res file.

操作如下：

首先准备个ICO图标。例如：myappico.ico
用记事本新建个文件，里面就写一行：

IDI_ICON1 ICON DISCARDABLE “myappico.ico”

保存改名为 myapp.rc并把它和你的图标myappico.ico一起复制到你的QT工程项目的目录。
用记事本打开你的QT工程文件（如 “myapp.pro” ），在里面最后新添一行

RC_FILE = myapp.rc

保存，编译你的工程，成功了吧。