Objective: To analyze factors impacting mental health status of medical students based on ecological systems theory, so as to provide reference for the mental health promotion system for medical students. Methods: In June 2024, 1 760 medical school students randomly selected from 19 different kinds of medical colleges in eastern China by stratified cluster were surveyed using questionnaires and expert interviews. Descriptive statistics, cross analysis, hierarchical linear regression analysis, structural equation models were used for data analysis. Results: Medical school students had higher satisfaction with the school (65.85%) and a great sense of perceived social support (57.16%). Furthermore, 91.14% of the students had normal interpersonal relationships. However, 44.89% reported that their mental health was impacted by high level of depression. The hierarchical linear regression analysis showed that the mental health outcomes of the medical students were positively predicted by higher perceived social support scores ( β =-11.40), institutional satisfaction ( β =-4.85 ), and lower help seeking stigma scores ( β =9.31) ( P <0.05). The structural equation modeling showed that the status of both perceived social support and self help seeking stigma had significant impacts on depression severity ( β =-0.32, -0.53) and interpersonal relationship sensitivity ( β =-0.31, 0.58) among medical students ( P <0.01).Through expert interviews, collaborations between the school and the tripartite organization (families, universities and society) was of growing importance. Conclusions Perceived social support and self stigma have a significant impact on the mental health status of medical students. The problem of self stigma of medical students should be paid attention to. Therefore, families, universities and society should work together to improve the mental health of medical students.