Objectives To explore the risk factors influencing the mental status of unmarried female youth.Methods A cross-sectional survey and a qualitative interview were adopted. 1 200unmarried female volunteers (600 with IA) who aged 15-29 years in Yibin city were investigated, and 8 focus group discussions (FGDs) and 8 in-depth interviews were conducted. Except the investigation of subjects personal information, econ-socio status,sexual behavior, contraception and reproductive health problems they face, two selfreporting scales, CES-D and SAS were used for assessment of depression and anxiety of the subjects.Results 1) Depression and anxiety among unmarried female youth investigated in current study are relatively common. Proportions of the females with depression and anxiety to the total sample are 27.4% and 33.4%, respectively; 2) Depression and anxiety of the females with IA are more serious than that of the female without IA.Proportions of unmarried females with IA have depression and anxiety to the total unmarried females with IA are 3.45 times and 2.61 times that of unmarried females without IA have depression and anxiety to the total unmarried females without IA,respectively; 3) IA is one of the key risk factors influencing depression and anxiety of unmarried female youth. Other risk factors are lack on basic knowledge about sex/STD/HIV/AIDS, reproductive tract infections, relatively lower income, age at sex debut is relatively younger, etc. In addition, multiple sex partners and repeat pregnancies were risk factors influencing anxiety of unmarried female youth.Conclusion Depession and anxiety was more popular in unmarried females with IA.Intervention for improving mental health of unmarried females should be developred.