In this paper,we analyse whether the Chinese A share stock markets exhibit excess volatility by employing the VAR methodology based on log-linear RVF of Campbell&Shiller(1989). According to the research result, relative to the intrinsic value implied by dividends,Chinese A share stock markets always exhibit excessive voltility for the period of 1994 to 2009. It is difficult to explain the stock market volatility puzzle of China's stock market , no matter we run constant excess return model or V-CAPM model. We try to explain the reasons by studying the stock market sentiment index, and find evidence of an interaction mechanism between investor sentiment and excess volatility. And One more meaningful result is that adding the stock market sentiment index to our model can provide extra explanatory power for the excess volatility of the stock market.