摘要Background Sexual and reproductive health among adolescents have become increasingly important and aroused international concerns.In this study,we investigate sexual knowledge,attitudes,sexual behaviors,the unwanted pregnancy and the abortion rate and to explore related determinants among college students in Beijing.Methods This study is based on a cross-sectional survey of college students' knowledge,attitudes and behavior.Multistage cluster sampling was used to select subjects in Beijing.The self-questionnaire designed by our research group including general information,knowledge,attitude and behavior about sexuality was used to collect information.A total of 2003 questionnaires were collected from June to July 2010.Results The data showed that most of the college students lacked knowledge about reproductive health.Only 17.9％ of the respondents knew the appropriate time of abortion.Data also showed that the respondents had high-risk attitude about sex,58.7％ could accept premarital sex,and 29.7％ had negative attitude towards contraception.Moreover,sexual activity of the respondents was active.Data showed that 18.5％ of the respondents had had sexual activities.Significantly more boys than girls had sex (X2=73.374,P ＜0.001 ).Among the boys and girls who reported sexual history,43.1％ of the boys had impregnated girlfriend and 49.3％ of the girls among those people who have sex had unwanted pregnancies.Logistic regression analysis showed that the variables the gender (OR=3.12,95％ Cl:2.39-4.11 ),grade (OR=1.78,95％CI:1.40-2.26),specialty (OR=1.35,95％ CI:1.12-1.74),family situation (OR=1.66,95％ CI:1.15-2.38),score of knowledge (OR=0.74,95％ CI:0.58-0.95) and attitude to sex activity (OR=0.09,95％ CI:0.04-0.22) had a significant effect on having sexual behavior.Conclusions College students lack knowledge and methods to avoid risky sexual behaviors in Beijing.College students have high-risk sexual attitude and behaviors.Therefore,suitable and effective sex health measures to protect college students would be strongly recommended.