Abstract:OBJECTIVE To investigate the status of freshman’s sexual behavior in Yunnan province, to understand the character⁃ istics of freshman’s sexual behavior, to analyze the influencing factors of sexual behavior, and to provide theoretical basis for target⁃ ed sexual education. METHODS The stratified multi-stage sampling method was used to select 3 undergraduate colleges and 3 ju⁃ nior colleges in Yunnan province, and conducted surveys through self-designed questionnaires. RESULTS The incidence of sexual behavior among freshmen in Yunnan province was 20.2% . The influencing factors of freshman’s sexual behavior include gender, school type, monthly living expenses, whether there were male (female) friends, students’ attitudes towards sexual behavior during college. Undergraduate students believe that their demand for sex education courses was better than that of junior colleges(P＜0.05). CONCLUSION Sex education for freshmen was of great significance. Health education should be carried out in various ways, focus⁃ ing on sex education for boys, higher monthly living expenses, male (female) friends, and freshmen in junior colleges.