In recent years, with its amazing online interactive promotion ability, e-commerce live streaming has attracted the attention of theoretical scholars and practical experts. This study takes “co-presence (CP) ” and “social presence (SP) ”, which are the prominent features of e-commerce live streaming, as the breakthrough point to explore the mechanism of the influence of co-presence and social presence on purchase intention. In this study, consumers with e-commerce live streaming watching experience are taken as participants, and the method of structural equation modeling is used. It is found that: presence significantly impacts flow experience and consumer purchase intention, while the impact of the two kinds of presence (SP, CP) is variable. the promotion effect of the two kinds of presence (SP, CP) on consumer purchase intention is completely mediated by flow experience. The mediating effect of co-presence on consumer purchase intention through flow experience is regulated by e-commerce live streaming topicality, but social presence doesn’t.