I wanna learn c++ by looking into the assembly language generated by visual studio. But i can't find a complete reference aoubt the usage of ml9. Is masm329 is tha same with ml9? If they are not the same, which one is better to write assembly language in a win32 system?

Its better to not write assembly language at all -- just let the compiler do the work for you. There is little, if anything, to be gained by hard-coding assembly language into a c++ program. And it makes porting to other operating systems next to impossible.