Abstract: Objective To develop a self-rated psychological sub-health questionnaire for medical students and to evaluate its validity and reliability.Methods Based on the results of clinical interview,case study,and literature review,we worked out a self-rated psychological sub-health questionnaire and 499 medical students were asked to complete the questionnaire.The data were analyzed with project analysis,exploratory factor analysis,and reliability and validity tests.Results The questionnaire was finally confirmed as a list of 35 items on 6 dimensions,including emotional response,learning difficulties,being world-weary or studying-weary,self cognition,somatization,and abnormal consciousness,with a cumulative contribution rate of 45.653%. The Cronbach α coefficients for the total score and 6 dimensions were 0.877 and 0.850,0.732,0.690,0.510,0.642,and 0.632,respectively.The related coefficients of 6 factors and the whole questionnaire were 0.834,0.664,0.651,0.438,0.645,and 0.607,respectively.ConclusionThe questionnaire has a good reliability and validity,and could be used as screening tool for assessment of psychological sub-health among medical students.