In China, major community e-commerce websites are focusing on increasing customer bases by converting members in their virtual communities into online buyers, which is one of the important ways of monetizing social traffic. Based on the Stimulus-Organism-Response (S-O-R) theory, this paper proposes and empirically tests a model of trust in virtual communities. We will collect data through online questionnaire surveys with users of Little Red Book, followed by structural equation modeling to analyze the influence mechanism of community e-commerce platform characteristics on consumers’ trust. The expected results will show the full mediation effects of interactivity and presence in the relationship between the quality of user-generated content (UGC) and the influence of key opinion leader (KOL) in virtual communities and trust. And consumers’ identity trust, cognitive trust as well as emotional trust will all significantly promote their actual purchases. This paper fills the research gap of trust mechanism on community e-commerce platforms. It also guides the community e-commerce platforms to encourage users to generate more high-quality content and promote major brands to cooperate with KOLs to accelerate the monetization of social traffic in virtual communities.