Social media enable celebrity to interact with their followers and enable followers to build the relationship through the interaction. Former research has found that openness and perceived interactivity are antecedents for parasocial interaction. In order to investigate the way to increase user’s engagement in celebrity’s social media page, this research examines the relationship between celebrity’s posts employ openness and perceived interactivity, other user’s posts employ openness and perceived interactivity, parasocial interaction, parasocial relationship, and social media engagement. Survey data were collected from 595 followers of one Chinese celebrity through an online survey. The results indicate that neither celebrity’s nor other user’s posts employ openness and perceived interactivity direct lead to user’s social media engagement. However, PSI and PSR, which increased by celebrity’s and other user’s posts employ openness and perceived interactivity, have a positive relationship with user’s social media engagement. It provides support for the mediating role of PSI and PSR to social media engagement.