Abstract: Objective To understand the relationship between premarital sexual behavior and attitude with AIDS-related knowledge among undergraduates in Xinjiang,and to provide reference for sexual education and HIV/AIDS prevention.Methods A stratified cluster sampling method was used to recruit 2 182 college students from 5 universities in Xinjiang.Anonymous surveys were conducted by using self-administered questionnaires.Results The prevalence of sexual behavior of undergraduates in Xinjiang was 21.9%(477/2 182);9.6%(209/2 182) of the students had a positive attitude towards premarital sexual behavior,and 37.8% (824/2 182) of respondents reported understanding with partner's sex history.The AIDS knowledge scores among students with and without sexual behaviors were (6.41±2.92) and (8.82±2.38),respectively.The difference was statistically significant (P<0.01).Multivariate logistic regression analysis showed that risk factors of sexual behavior included ethnic minorities(OR =3.457),no understanding with partner's sex history(OR=1.817),without thinking before sexual relationship(OR=1.123),and ambiguity on sexual behavior(OR=1.926).The protective factors included being female(OR =0.612),medical major(OR=0.372),conditional acceptance of premarital sex(OR=0.479),and opposition towards premarital sexual behavior(OR =0.150),as well as AIDS knowledge score higher than 10(OR =0.544).Conclusion Sexual behavior among college students in Xinjiang is quite common.Sexual education and HIV/AIDS related knowledge should be strengthened,and individual active approach to AIDS-related knowledge need to be improved among Xinjiang college students as well.