Social media has become an emerging trend in the work of enterprises and organizations, but few studies have explored the specific behavior and its influence mechanism of social media adoption in the workplace. This paper divides the social media use behavior in the work context into two types: reinforced use and varied use. Based on the technology acceptance model, this paper combines TAM and motivation theory to build a research model on the motivation of using social media in work and its influence on the use behavior. Through empirical analysis of questionnaire data in practical work, the research results show that the three motivations positively influence adoption intention through the mediation of perceived usefulness, and the intention is positively correlated with the two behaviors.