With a panel data of 14 commercial banks from1994 to 2003 in China and after introducing the dummy variable of official implicit insurance,this paper tests these banks' market discipline through their reflection of the real deposits growth rates to their risks and finds that the official implicit insurance not only covers the state-owned banks,but also all the other banks in China,which causes the weaker market discipline.The implication for the reform of the Chinese banking is that China should give up the official implicit insurance as early as possible and set up the explicit deposit insurance system suitable for Chinese situations.