Abstract: Objective To explore the influence of marital status on HIV infection status and related high risk behaviors among men who have sex with men (MSM) and provide scientific evidence for developing effective prevention and control strategy. Methods A total of 744 unmarried MSM and 455 married MSM were recruited by snowball sampling. Questionnaire survey was conducted and blood samples were taken to detect HIV and syphilis antibodies among them. Results There were no significant differences in AIDS related knowledge awareness, homosexual behavior and HIV infection status between married MSM and unmarried MSM. There was a significant difference in heterosexual behavior between two groups, and married MSM had more risk heterosexual behaviors than unmarried MSM. Conclusion In married MSM, marital status can not restrict their high risk homosexual behavior. Furthermore, they are more likely to spread HIV to women through heterosexual behavior. To control HIV transmission effectively, targeted behavior intervention is necessary for married MSM.