Social dynamics is a social networking service that allows users to input updates including letters, pictures, videos and share them with their social friends. Previous research mainly focus on the application of dynamic messages in the fields of communication science and economics. Based on impression management theory, this paper studies the influencing factors of users' dynamic message deleting intention on social networks. The results show that impression management performance and social network fatigue significantly affect user's intention to delete the dynamic messages. While message sender factors, such as self-monitoring, interpersonal interaction and image promotion; social platform factors such as information overload and social overload, indirectly influence the deleting intention through intermediary variables. This paper makes up for the lack of relevant empirical research, making users more social flexibility and effectiveness, thereby enhancing social validity, and have some practical implications for social networking services platforms.