[Purpose/significance] With the development of internet and information technology, more and more social media have been begun to build a new business model of “community + e-commerce”. This paper aims to explore the user knowledge sharing on their consumer behavior in the content community, so as to provide a management strategy for improving the purchasing behavior of users in the community. [Method/process] This article took “Little Red Book” as an example to analyze its internal operation mechanism, and based on Szulanski’s knowledge transfer model, built the influencing factor model of the knowledge sharing process on consumer purchase behavior in the “Little Red Book”. Finally, it took the users of the “Little Red Book” as the survey object, through the data of the questionnaire survey for empirical analysis. [Result/conclusion] In social media, knowledge sharing among users can be divided into four stages: knowledge generation, interaction, integration and feedback, in which user interaction, perceived risk and the professional ability of the recipient have positive impacts on their purchase behavior; The knowledge sharing process further influences the users’ willingness to purchase through the intermediary role of knowledge sharing content and degree, and the knowledge sharing content has a greater impact on it, which also indicates that in social media operations, enriching and improving community content and strengthen users, enhancing user interaction and reducing the perceived risk of users are the key to promoting user purchases.