This paper studies the spread of fake news on social media platforms and analyzes theinfluence mechanism of echo chamber effect on the formation and reinforcement of fake news belief.Through the analysis of cognitive bias, group information inclusion, group emotional identificationand opinion leaders' voice, the corresponding governance strategies are put forward. The study foundthat social media platforms can manage the spread of fake news by setting up cross-verification userfeedback mechanisms, optimizing recommendation algorithms, and promoting media literacy "microcourses."These governance strategies will help reduce the negative impact of fake news on publicdiscourse and social cognition, promote the healthy development of social media platfor.