In this study, the authors use selfdetermination theory to investigate how training support, support from parents and teachers, peer pressure from friends, and Internet selfefficacy affect the intrinsic motivations (enjoyment and curiosity) of high school students to use the Internet, and the outcomes of these motivations. 　We find out that training support and parental support do not have significant positive impacts on intrinsic motivations, but teacher's support significantly affects curiosity. Peer pressure and Internet selfefficacy positively relate to enjoyment and curiosity. As to the outcomes of intrinsic motivations, both enjoyment and curiosity lead to flow state. However, only curiosity and flow state have positive effect on online exploratory behavior, and enjoyment is found to have negative effects on online exploratory behavior. The analysis on the mediating effects of gender in the model show that girls are more intend to be impacted by the influence from school, teachers and parents than boys.