Based on the monthly data of the Shanghai and Shenzhen stock markets from January 2012 to December 2017, the number of newly established funds, turnover rate, priceearnings ratio, trading volume, new account opening, and consumer confidence index were selected. Principal component analysis was used. The method is to construct a comprehensive indicator of investor sentiment and empirically analyze the relationship between investor sentiment and stock price. The results show that the Shanghai and Shenzhen 300 Index and investor sentiment have a stable equilibrium relationship in both longterm and shortterm periods; the fluctuation of stock price and that of investor sentiment have a lagging effect on investor sentiment; the Granger causality test shows that Stock price volatility is the Granger reason for investor sentiment fluctuations, indicating that stock price volatility can cause investor sentiment fluctuations; investor sentiment volatility has negative impact on their own emotions, and stock price volatility has a positive influence on investor sentiment. And both are more affected by themselves.