Where is the best place to shop name brand clothing in China? please help

To get brand clothes, I suggest you get at Beijing, Shanghai or Hong Kong.
Beijing, you can go to Xidan, where there are many large shopping malls selling brand clothing.
Shanghai Nanjing Road can also be a good choice for you. There you will many choices.
At Citygate of Hong Kong, you will find many brand clothes with discount. Go there and you can gain a lot.