Hello niequanwei@aochutec.com,
I think you should ask on the Code Warrior community (here) to get an answer from more experienced guys when it comes to Code Warrior. Just keep in mind to mention that you'll probably have a custom linker file and a custom makefile, if you want to use the code generated by Model-Based Design Toolbox.
As far as downloading through the RappidTool, you can do it after you manage to generate the .ELF file, but keep in mind that first you'll have to flash the .rbf onto the board, and only then download your application.
Hope this helps,
Razvan.