Abstract: Objective To describe the status of sexual knowledge,sexual attitude,sexual behavior and sexual self-concept and their influencing factors among pregnant adolescent girls.Methods The survey was conducted among 245 unmarried pregnant adolescent girls recruited from hospitals in Kunshan city of Jiangsu province with a self-designed questionnaire.Results Among the pregnant girls,the average score was 3.29±0.43 for sexual knowledge,2.66±0.49 for sexual attitude,2.66±0.49 for sexual behavior,and 2.93±0.46 for sexual self-concept and the average scores of sexual attitude and self-concept were relatively low.Education background,perceptions of parents' marital relationship,and parent-child relationship affected the average score of sexual knowledge(F_{education background}=6.97, P<0.01;F_{parental marital relationship}=9.36, P<0.001;F_parenthood=5.46, P<0.01); the parents' marital relationship had effects on their girls' sexual attitude(F_{parental marital relationship}=4.79, P<0.01) and sexual behavior(F_{parents' marital relationship}=7.22, P<0.05),with statistically significances.The parenthood had effect on their girls' sexual attitude(F_parenthood=3.83, P<0.05) and education background affected sexual self-concept of the girls(F_{Education background}=10.033, P<0.001); sexual knowledge(β=0.44, P<0.001)and sexual attitude(β=0.44, P<0.001) were significant direct predicators of sexual self-concept and could affect sexual self-concept indirectly through sexual behavior(β=0.44, P<0.001).Conclusion The overall situation of pregnant adolescent girls was not good and family factors and education condition were important influence factors of teenage pregnancy.