Hi, Where can I get copy of branded watches in Guangzhou? Is there is any place near canton fair?

The best place to go is Zhanxi Road near GZ main railway station. Nearby you can find the famous Southern Watch Trading Center.
From the Canton Fair, you can walk to Bazhou Station, and take subway line 8 there to Changgang. Transfer to line 2 and get off at the railway station. After getting off from exit E, walk westwards you can reach it.