Hazardous/harmful drinking among college students is increasingly becoming a global health concern. Previous studies have mostly paid more attention to the prevalence and risk factors of alcohol use disorder based on the public health approach, and less is understood about psychological mechanisms and protective factors of problem drinking behavior. Grounded in the framework of developmental assets, this study explored the predictive effect of external assets (i.e., social connectedness) and internal assets (i.e., self-concept clarity and drinking refusal self-efficacy) on hazardous/harmful drinking among Chinese college students. Participants were 598 college students with a mean age of 19.41 (SD = 1.21) years. The results of structural equation modeling showed that social connectedness negatively predicted college students' hazardous/harmful drinking. Moreover, our path analyses revealed a serial mediation among these variables: students with high social connectedness tended to report high self-concept clarity, which in turn increased drinking refusal self-efficacy, and consequently decreased the level of hazardous/harmful drinking. This study revealed the mechanisms underlying how external and internal assets predict risky drinking among college students. These findings made significant contributions to prevention and precision interventions for college-aged youth with drinking problems.