Abstract: Based on the comprehensive collection of important policy factors that affect the rise and fall of the stock market, this paper evaluates the impact of policy variables on the stock market and obtains a curve of policy variables. It uses SPSS correlation analysis tool to calculate the correlation value between the policy variable curve and the stock market fluctuation curve, and Granger causality test to assist in verifying the interaction and relationship between the policy change and the stock market change. The results show that the econometric model can better explain the relationship between policy changes and Shanghai stock index changes. Under the normal stock market conditions, the volatility of China's securities market is obviously affected by policies, and the two changes are highly correlated. Therefore, if the short-term economic policy changes frequently and unexpectedly, it will increase risks and difficulties of investment in China's stock market.