With the development of the times continuously, the increasing popularity of the Internet and the maturity of its date base, the amount of date in human daliy study, life and work presents an enponentail growth, when the collected data is large and more complex, it is urgent to collect data from a large amount of data and extract valuable information. Taking Sina Weibo as an example, this paper uses web crawlers to crawl data, and analyzes the emotion of weibo hot search data through Bayesian network model, which is of great significance for controlling the direction of public opinion.