Abstract: Objective To study the factors associated with characteristics of heterosexual intercourse among men who have sex with men(MSM)in Beijng.Methods Between November 2006 and February 2007,MSM were investigated to collect their socio-demographics and high risk sexual behaviors.Results 47.1%(255/541)of the MSM had sex with female.In the multivariate Cox proportion hazard regression model,education(HR=1.98,95% CI=1.54～2.56)and sexual orientation(HR=2.92,95% CI=2.06～4.15)were the factors independently associated with the firstheterosexual intercourse.13.9%(75/541)of the MSM had sex with female in the past 3 months.Multiple logistic regression demonstrated that age>26(OR=2.0,95% CI 1.12,3.56),sexual orientation(OR=24.2,95% CI=11.1～52.6),and drunkeness in the last month(OR=2.6,95% CI=1.3～5.0)had significant statistic significance.Conclusion Intervention measures should be taken to stop HIV spreading from MSM to normal females.