According the Theory of Planned Behavior (TPB), personal behavior is determined by behavioral intention, which stems from a person's attitude toward the behavior, subjective norm, and perceived behavioral control. However, in real world situations, personal behavior is formed within social networks, and the development of personal behavior is strongly influenced by social interaction. Therefore, how collective norms affect a person's behavior in a complex social network is a deciding factor in personal behavior, yet this is overlooked by the TPB. On the basis of TPB, this study combines with social network analysis to explore the effect of collective norms on behavioral intention. The research targets are college students in physical education elective courses. The findings of this study show that network centrality moderates a person's subjective norm and behavioral attitude. This complements TPB's oversight regarding the influence of collective norms on individual behavior.