where i can get GoPro Camera Accessories in shenzhen?any suggestion? thank you

It may be hard to get one in SZ, because there is not a special market for photographic equipments.
If you want to have a try, a local store called Shengdai Photographic Equipments Store on 1F, Wanshang Eletronic Products Market on North Huaqiang Road is suggested for you.
If you cannot find there, it is suggested to have a look at HK, which is close to SZ.