Objective: To explore effects of cumulative family risk in university students on individuals internalizing problems, to elucidate the mediating roles of perceived social support and self esteem in the relationship, so as to provide a basis for promoting university student s mental health. Methods: Using longitudinal design, 1 207 freshmen from a university in Tianjin were randomly selected and surveyed in November 2023 (T1) and November 2024 (T2). The instruments included the Cumulative Family Risk Scale, the Perceived Social Support Scale, the Self esteem Scale, and the College Student Mental Health Screening Scale. Structural equation modeling (SEM) was constructed, with Bootstrap method used to test mediating effects and to examine gender differences. Results: The results showed that cumulative family risk at T1 with internalizing problems at T1( r =0.30) and internalizing problems at T2 ( r =0.32) were significantly positively correlated (both P <0.01). Mediation analysis indicated that the independent mediating effect of perceived social support at T1，cumulative family risk at T1 and internalizing problems at T2 was 0.03 (95% CI =0.02-0.05), and the independent mediating effect of self esteem at T1 was 0.08 (95% CI = 0.06 -0.10) (both P <0.05). The chain mediating effect of perceived social support and self esteem at T1 was 0.02 (95% CI =0.02-0.03) ( P <0.05). Significant gender differences were observed in the path from cumulative family risk to self esteem ( β male =-0.24, β female =-0.35) and in the path from perceived social support to self esteem ( β male =0.41, β female =0.25) (all P <0.05). Conclusion Cumulative family risk reduces internalizing behaviors in university students via internal and external development resources, with gender specific mechanisms.