Objective: To describe bullying victimization of middle school students in Dalian and associated factors, so as to provide scientific basis for campus bullying prevention. Methods: The stratified cluster sampling method was used to select 2 540 middle school students from urban and rural areas in Dalian, who were investigated with campus bullying victimization and related factors. Results: The reported rate of campus bullying victimization among middle school students in Dalian was 25.11%. The rates of physical violence (5.99%, 3.66%) and verbal violence(24.93%, 15.87%) of male students were higher than that of female students( χ 2=6.56, 27.94, P <0.05). The rates of verbal violence (22.84%, 16.25%) and emotional neglect(16.84%, 13.18%) of junior high school students were higher than those of high school students( χ 2=14.21, 5.44, P < 0.05 ). The rates of physical violence(6.07%, 3.55%), verbal violence(24.58%, 16.05%) and emotional neglect(18.88%, 12.06 %) of rural students were higher than those of urban students( χ 2=7.72, 24.81, 19.64, P <0.05). Male students, junior high school students and rural students suffered more severe campus bullying than female students, high school students and urban students( Z =3.46, 3.75, 5.89, P <0.01). The structural equation model showed that academic performance (path coefficient -0.003) and father s education (path coefficient -0.004 ) have a direct negative effect on campus bullying behavior, while mother s education (indirect action coefficient -0.000 8), height(indirect action coefficient -0.000 3), father s education (indirect action coefficient -0.000 3) and weight (indirect action coefficient 0.000 2) indirect effects on campus bullying through academic performance. Conclusion The prevalence of campus bullying victimization among middle school students in Dalian is relatively high, which worths further attention to. Rural students, junior high school students and boys are more likely to suffer campus bullying. Improving academic performance might be beneficial for campus bullying prevention.