Adolescents’ perceived social support was positively associated with their academic achievement in western culture (e. g., Bahar, 2010; Domagala-Zysk, 2006; Rueger, Malecki, & Demaray, 2010). A few studies have examined the relationship between perceived social support and academic achievement in Chinese culture. The narrowness of the sample upon which most psychological researches have been conducted raises important questions about the generalizability of this research (Arnett, 2008). Few studies have examined the mediating processes between perceived social support and academic achievement. And there is few research, if any, examining whether the mediating effect depend on other factors. This present study aimed to explore the moderated mediation among perceived social support, coping efficacy, stressful life events, and academic achievement after controlling for demographic variables. A sample of 1687 adolescents of 6 schools (835 boys and 852 girls, Mage=14.91±1.56) was recruited in the study to complete self-report questionnaires. The self-report questionnaires used in this study included the perceived social support questionnaire, coping efficacy questionnaire, stressful life events scale, and academic achievement questionnaire. The results indicated that: (1) perceived social support was positively associated with adolescents’ academic achievement; (2) coping efficacy played completely mediating effect between perceived social support and adolescents’ academic achievement. Perceived social support had indirectly influenced academic achievement; (3) stressful life events moderated this mediation effect of coping efficacy. In the context of low stressful life events, with the increase of coping efficacy, adolescents’ academic achievement had obviously ascending trend (b =0.29, t = 7.62, p < 0.001). In the context of high stressful life events, with the increase of coping efficacy, adolescents’ academic achievement had ascending trend (b =0.13, t = 4.23, p < 0.001). In other words, with the increase of stressful life events, the effect of coping efficacy on academic achievement decreased. The theoretical and practical implications of the results were further discussed. Firstly, we should attach importance to the effect of perceived social support on adolescents’ academic achievement. Secondly, we should help adolescents to improve the level of coping efficacy, and adequately reduce adolescents’ stress.