Objective:To investigate the status of psychological stress and explore its influence factors in medical student vol-unteers,so as to provide evidence for optimizing stable long-term university voluntary services.Methods:A questionnaire survey was conducted on 1139 medical student volunteers using the Volunteer Service Participation Questionnaire,Chinese version of per-ceived stress scale(CPSS)and college students'speciality identity questionnaire.Data were analyzed using t-test,ANOVA,Pear-son correlation analysis,and multiple linear stepwise regression.Results:The total score of psychological stress in medical student volunteers was(16.16±7.58),of which 11.30%were at a high level.Multiple linear stepwise regression analysis revealed that spe-ciality identity and grade were the influencing factors of psychological stress(adjusted R2=0.261,F=185.934,P<0.001).Psy-chological stress level decreased with increasing total professional identity score(β=-0.478)and with increasing grade level(β=-0.175).Conclusion:Few medical student volunteers had excessive psychological stress levels.Higher level of professional identi-ty and higher grade can reduce the psychological stress level of medical student volunteers.In order to ensure the stable development of medical student volunteer service,universities should pay attention to the psychological condition of medical student volunteers,create a comfortable and harmonious volunteer environment,and integrate professional education into volunteer service.