With the emerging of user numbers in online social networking, the social commerce has been paid
attention by both academic and business fields. As a new type of communication tools, research findings
have reported that the user produced contents (UGC) in social networks are affecting user feeling,
shopping efficiency and purchase intention, etc. However, as a new kind of e-business pattern, related
theory in social commerce is not fully developed in lots of perspectives. Among all the to-be-discovered
topics, what factors are affecting the consumer’s intention in social commerce is one of the most
interesting and urgent topic. This paper proposed an empirical model, whereas the consumer knowledge,
user’s social commerce cognition and social support are related with users’ purchase intention. Data is
collected via online questionnaire and the models are tested using structural equation model (SEM). The
test results find that social commerce cognition and social support are positively related with social
commerce purchase intention. Different from what is hypothesized in previous literature report, the
consumer knowledge has a negative effect on social commerce purchase intention. The reasons of this
phenomenon is explained that the social commerce development is still in an early stage, consumers has
higher expected value compared with that of the e-commerce, but with the knowledge increase or
cumulated about the social commerce, they are disappointed. That leads to the negative effect on
purchase intention. Companies can make up this shortfall by developing market strategies more on social
support factors since social support has more impact on users’ purchase intention. In the future, what
lead to the consumer knowledge being negative effect on purchasing intention needs to be further
investigated.