With the rapid growth of internet technology, social commerce has played an important and central role in the online shopping area. Thus, we focus on the factors that influence on the adoption of social commerce. This study analyzes the relationship between perceived risk and the shopping motive in social commerce, and investigates whether the shopping motive significantly impact the purchase intention of the social commerce. The perceived risk is comprised of social risk and psychology risk, and the shopping motive is formed from personal motive and social motive. Finally, we analysis a moderating effect of collectivism. The results indicated that the personal motive was negatively affected by the social risk and psychology risk, and social motive was negatively affected by the psychology risk. The social risk and psychology risk had negative effect on the purchase intention, and personal motive and social motive had positive effect on the purchase intention of the social commerce. Finally, low collectivism seems to have the negative effect of the purchase intention by the perceived risk. The implications of integrating perceived risk and shopping motive into the proposed social commerce adoption model are discussed.