Abstract: Objective To understand the status of sex-related behavior behavior among high school students and its influencing factors in Guizhou Province,and to provide a reference for adolescent sex education for relevant departments.Methods Multistage stratified cluster random sampling method was used to conduct an on-site anonymous questionnaire survey among 2 523 students randomly selected from 6 high schools,and the results were analyzed by using chi-square test,and multivariate analysis was conducted by using Logistic regression analysis.Results The reporting rate of marginal sexual behavior in high school students in Guizhou was 36.7%,and the rate of sexual behavior was 4.7%.The reporting rate of sexual behavior in rural areas (6.0%) was higher than that in urban areas(3.5%) (x2 =8.876,P<0.01),and both the reporting rate of boys' marginal sexual behavior (43.2%) and sexual behavior (8.2%) were higher than those of girls (31.6%,2.0%),the differences were statistically significant (x2 =35.444,54.021,P<0.05);Watching pornographic books/audiovisual products,smoking and drinking were the risk factors for marginal sexual behavior(OR=2.319,1.985,2.569,P<0.01),while boys,watching pornographic books / audiovisual products,and smoking were risk factors for high school students' sexual behavior(OR=2.295,4.720,2.021,P<0.01).Conclusion High school students in Guizhou Province are reported of high rates of marginal sexual behavior and sexual behavior.Therefore,the senior high school students who are boys,come from rural areas,watch the pornographic books and audiovisual products and develop the smoking habit should be the focus of health propaganda and education.