Behavioral finance believes that investors are vulnerable to the impact of their own emotions when making investment decisions, and investors'behavior is the direct cause of the volatility spillover between financial markets. From the perspective of the sentiment index, this paper makes a research on the influence of Internet fund market on stock market, on the basis of text mining technology and random forest-principal component analysis method on Sina Micro-blog to build big data investor sentiment index from April 2014 to July 2016. The results show that the Internet fund market has volatility spillover effect on the stock market.