Background Childhood sexual abuse (CSA) is a serious public health problem worldwide. Objectives: We reported the prevalence of CSA and examined its association with risky sexual behaviors and adverse reproductive health outcomes among college students in China. Participants and setting: Participants were 17,966 college students from 130 colleges in Eastern, Central, and Western China, who completed the online questionnaire in January August 2015. Methods: Data were obtained from a cluster-random Internet-based survey. Multivariate logistic regression analyses were employed: risky sexual behaviors and adverse reproductive health outcomes were outcome variables, and various types of CSA were predictor variables, while adjusting for socio-demographic and lifestyle characteristics. Results: The overall prevalence of any type of CSA was 27.5%. Most perpetrators were friends/ acquaintances (34.6%) or intimate partners (24.7%) of the victims. Respondents who reported penetrative CSA were strongly associated with regular unprotected sex (odds ratio (OR): 3.0, 95% confidence interval (CI): 2.2-4.0), early sexual debut (OR: 5.5, 95% CI: 3.3-9.1), having genital tract symptoms in the last 12 months (OR: 5.0, 95% CI: 4.1-6.0), unintended pregnancy (OR: 6.2, 95% CI: 4.2-9.0), and induced abortion (OR: 5.5, 95% CI: 3.7-8.2) (for boys, the survey asked about history of unintended pregnancy and induced abortion of their sexual partners). A dose response relationship was found across non-contact, contact, and penetrative CSA. Conclusions: CSA experience may increase the likelihood of risky sexual behaviors and adverse reproductive health outcomes in victims' early adulthood.