Abstract: Objective To study the status of reproductive health related behaviors among out-of-school adolescents in Yunnan province and Shenzhen city,and to explore the social-psychological influencing factors of the behaviors.Methods A cross-sectional study was conducted in Yunnan and Shenzhen and totally 862 out-of-school adolescents aged 15-24 years were recruited with accidental sampling for a survey with a self-administrated questionnaire.Results The ratios of behaviors of holding hands,hugging,kissing,caressing the body,and sexual intercourse with the opposite sex among the adolescents were 92.5%,85.7%,75.9%,60.2%,and 54.5%,respectively and 45.7% of the adolescents who had sexual experience did not use condom in the latest sexual intercourse;the ratio of people having two or more sexual partners was 62.6%.Binary logistic analysis showed that age and marital status of the adolescents were risk factors of condom use in the latest sexual intercourse(P<0.05),with the odds ratios (ORs)of 2.318(95% confidence interval95%CI:1.601-3.356)and 0.367(95%CI:0.190-0.709),while,general well-being of the adolescents was a protective factor with the OR of 0.971(95%CI:0.955-0.987).Survey area,age,gender,migrant times were the risk factors of having more than one sexual partner(P<0.05),with the ORs of 2.690(95%CI:1.511-4.790) for livig in Kunming city,4.644(95%CI:1.007-2.729)for living in Shenzhen city,4.464(95%CI:3.180-6.783) for female,1.225(95%CI:1.113-1.349) for older age,and 1.102(95%CI:1.003-1.022) for having long time of working;general well-being of the adolescents was a protective factor with the OR of 0.969(95%CI:0.953-0.986).Conclusion The incidence of reproductive health related risk behaviors among the out-of-school adolescents in Yunnan and Shenzhen is high.The general well-being is negative correlated with reproductive related risk behaviors.