Background Previous studies have shown evidence of health-related risk behaviors among women who have sex with women (WSW),such as sex with men,multiple bisexual partners,and drug use.Women who have sex with women have also been known to avoid routine physical examinations and conceal their same-sex history from physicians,which can affect their ability to receive an accurate diagnosis and treatment.No previous research has targeted women who have sex with women in China.We sought to describe women who have sex with women in China and explore risk factors for their reproductive tract infections (RTI)/sexually transmitted infections (STI).Methods Participants were recruited through outreach in venues and online for a cross-sectional study.Data were collected using interviews and laboratory tests.Results We recruited 224 women who have sex with women.In the year preceding their participation in the study,92％ (206/224) of women reported sexual relations with women.The RTI rates were:gonorrhea (15.8％),chlamydia (3.5％),syphilis (0.5％),bacterial vaginosis (14.4％),hepatitis B virus (HBV) (0.9％),hepatitis C virus (HCV) (0.5％),and candidiasis (6.9％).No HIV or herpes simplex virus (HSV) positive cases were detected.Factors associated with gonorrhea infection were non-Beijing local residency (odds ratio (OR)=2.1,95％ confidence interval (Cl):1.2-3.8) and genital-genital contact (OR=3.1,95％ Cl:1.3-7.2); factors associated with curable STI (excluding bacterial vaginosis,candidiasis,HBV and HCV) were non-Beijing local residency (OR=1.9; 95％ Cl:1.2-3.0) and bleeding during or after sex (OR=18.1; 95％ CI:5.2-62.6); and the factor associated with RTI (including all the infections tested) was bleeding during or after sex (OR=37.8,95％ Cl:11.2-127.4).Conclusions Behaviors that may cause RTI/STI exist among Chinese women who have sex with women.Researchers should consider these behaviors when planning corresponding prevention and interventions.