Abstract: ObjectiveTo study the relationship between physical exercise and sleep quality in medical students.MethodsThe Pittsburgh Sleep Quality Index(PSQI)and Physical Exercise Degree Questionnaire were adopted to survey 1602 medical students in Fujian province.ResultsThe total prevalence of poor sleep was 27.9% in all students investigated.Average PSQ I score was(6.24±2.44).Average physical exercise score was(15.19±16.62).37.1% of the students with twohours strenuous exercise before sleep was not conducive to sleep.The score of PSQI of lower amount of exercise group was significantly higher than that of other two sorts of students.There was no statistical significance between middle exercise group and higher exercise group.Correspondence analysis showed students with middle and higher amount of exercise slept well,students of lower amount slept worse.ConclusionModest exercise was helpful to sleep quality,but strenuous exercise was not conducive to sleep,participating in adequate physical exercise in the afternoon or evening should be strengthened,so as to improve sleep and promote physical and mental health.