This article emphasizes whether such political events as CPC National Congress and National People' s Congress(NPC) and Chinese People' s Political Consultative Conference(CPPCC) do some impact on China stock market.We take the 16th and 17th CPC National Congress as the sample events.Besides,NPC and CPPCC in 2002,2005 and 2007 are also considered.We use event study to analyze these cases.After analysis we find that such political events do have some impact on China stock market and China stock market is a policy market without policy efficiency.The main reasons are the government mandatory institutional arrangement、the lack of continuity and stability in policy mechanisms and the existence of those investors with internal message.Base on these analyses,this article also proposes the corresponding policy recommendations.