With the rapid development of Internet social platforms, some extreme remarks, online rumors and negative thoughts often appear in various news, Weibo, WeChat, and promotions, which seriously affect social stability, stability and unity. How to dig out public opinion information from these media information texts and effectively monitor and manage online public opinion is of great significance. Text sentiment analysis is the main research direction in the field of natural language processing. Its main research focuses on word vector representation, text feature extraction, model establishment, etc. This article explains the current research status of sentiment analysis using machine learning technology in the industry, and proposes an improved ML-SVM (Machine learning support vector machines) public opinion information classification algorithm based on machine learning. A new public opinion word discovery mechanism is established through the characteristics of public opinion information and Shannon's law, which solves the problem of insufficient features of the training text set; in order to better measure the close relationship between public opinion information, a public opinion text information update algorithm is established, and through different data sets Simulation experiments and comparative analysis verify the effectiveness of the algorithm in this paper.