Objective: To examine the prevalence and associated factors of seeking casual male sexual partners among men who have sex with men (MSM) students in Guangzhou, and to provide a reference for health education and intervention. Methods: A cross-sectional study was conducted to recruit 189 MSM students aged 18 and 28 via voluntary counseling and testing (VCT) clinics, Lingnan partners and Zhitong charity from May 2017 to April 2018. An anonymous electronic questionnaire was administrated to collect information on sociodemographic and sexual behavior characteristics. Chi-square test and non-conditional Logistic regression analysis were performed to explore the associated factors of casual homosexual behavior among MSM students. Results: In the past 6 months, 63.49% (120/189) of them reported casual male partners, and the rate of consistent condom use was 61.67%(74/120). Multivariate Logistic regression analysis showed that participants who had multiple sex partners in the past 6 months were more likely to seek male casual partners(aOR=9.13, 95%CI=4.27-19.53). Individuals who used recreational drugs before sex were at a higher risk of having casual sex behaviors(aOR=3.06, 95%CI=1.08-8.62). MSM students who had steady homosexual partners had a lower risk to seek casual sex(aOR=0.43, 95%CI=0.19-0.98). Conclusion The proportion of seeking casual male sexual partners among MSM students in Guangzhou was relatively high. The publicity and education should be strengthened among those who had multiple sex partners, with no steady homosexual partners and used recreational drugs before sex, to reduce the casual sex behaviors.