Social commerce grows as the growth of sophisticated e-commerce and social media. Based on empirical research about consumer purchase intention, various influencing factors of purchase intention was identified. In this study, we conducted a research about influencing factors of consumer purchase intention : (1) familiarity, (2) information seeking, (3) trust, (4) social presence, (5) perceived social value and (6) perceived utilitarian value. We also observed the role of trust as mediator between social presence and purchase intention. 189 questionnaires were constructed to social commerce users who experienced in among instagram, Kaskus, Eventbrite, groupon and so on. Structural equation modelling (SEM) is used in our research model and tested by partial least squared (PLS). The result are : (1) social presence and trust onfluence consumer purchase intention, (2) trust can be an intermediary between social presence and purchase intention.