Objective: Refine and understand the characteristics of different types of bystanders, in order to maximize the exploitation and utilization of bystanders as potential resources for anti bullying, so as to provide more targeted guidance for the formulation of intervention programs. Methods: In this study, 1 279 students from two middle schools in Beijing and Anhui Province and two high schools in Guangdong Province and Guangxi Zhuang Autonomous Region were administered with Participation Role Questionnaire (PRQ) and Peer Nomination Questionnaire. Results: There was a significant difference between male and female in the role of onlooker( χ 2=96.92, P <0.01). Female students were more likely to play the role of defender and outsider, while male students were more likely to play the role of reinforcer( χ 2=31.87, P =0.01). And there were significant differences in the distribution of bystander roles in different grades. The chi square test results were( χ 2=456.26, P <0.01). Conclusion The bystander plays an important role in the occurrence of bullying incidents. It is an important direction of school bullying intervention programs to promote the positive transformation from passive bystander to active bystander.