The main purpose of this study was to explore the relationships among social support, resilience and mental health of inmates in different background variables, and the correlation among them. The research instruments of this study included Social Support Scale, Adolescence Learning Attitude Scale and Positive Mental Health Scale. The study was conducted in Taipei Detention Center. Inmates given 3 years imprisonment below and classified mix-up confinement were selected as subjects, and 293 inmates were selected by questionnaire. The data was statistically analyzed with descriptive statistics, t-test, ANOVA, Pearson correlation analysis and multiple regression analysis. The main findings are as follows: There were positive correlations among social support, resilience, and mental health. Resilience and social support indicate mental health. Furthermore, social support had a partial mediating effect between resilience and mental health.