Abstract: Privacy fatigue has become a characteristic of the times that cannot be ignored by modern mobile social media users. This study constructs the influencing factor model of privacy fatigue from empirical data and further combs the relationship between factors to reveal the generation mechanism of user privacy fatigue. By adopting the grounded theory research method, this study collects data through in-depth interviews with 18 social media users, combs and summarizes the influencing factors of privacy fatigue through the stages of principal axis coding, selective coding, and theoretical saturation test, and uses the interpretative structural model method to analyze the internal relationship between various factors. The results show that perceived cost is the direct factor affecting user privacy fatigue, self-efficacy and perceived trust are the root factors, and perceived control and self-cognitive bias play a vital role in the formation of user privacy fatigue. On the basis of summarizing the influencing factors of social media users' privacy fatigue, this paper further combs the relationship between the factors, which not only provides a theoretical reference for understanding the influencing mechanism of users’privacy fatigue but also provides a new research perspective for the prediction of users’privacy behavior in the future.

Key words: Privacy fatigue, Social media, User behavior；Interpretative structure model；Grounded theory