，通过搜索Qt Assistant，发现有如下说明：
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.
那么做法就清楚了：
第一步，准备个ICO图标。
例如：myApp.ico 用任何的文本编辑器新建个文件
里面写上一行：
IDI_ICON1 ICON DISCARDABLE "myApp.ico"
第二步，保存改名为 myApp.rc并把它和你的图标myApp.ico一起放置到你的Qt工程的目录里面。
第三步，用文本编辑器打开你的Qt工程文件（如 myApp.pro ），在里面的最后面新添一行：
RC_FILE = myApp.rc
第四步，在程序中添加如下代码：
//app是程序中唯一的QApplication对象
app.setWindowIcon(QIcon("myApp.ico"));
注意：如果你的myApp.rc和你的图标myApp.ico不是在你的Qt工程目录里面，那么最后一句的代码中请指明图标文件的路径。
本文来自CSDN博客，转载请标明出处：http://blog.csdn.net/qter_wd007/archive/2010/10/31/5978188.aspx
