Abstract: Objective To study the sleep quality and its influencing actors for improving sleep quality in medical students.Methods Totally 878 medical students were selected with multistage randomcluster sampling.Pittsburgh Sleep Quality Index(PSQI)was used to evaluate the sleep quailty and the results were analyzed with the SPSS 11.5 software.Results The mean PSQI score of medical students was 5.36±2.73.18.00% of the students were poor sleepers.No statistical significance was found between different gender,specialties,on line time,monthly income per capita of the family,body mass index(BMI),smoking status,drinking status(P>0.05).Statistical significance was found between different grades,study time,living environment,physical exercise(P<0.05).Rseults of multiple stepwise regression indicated that grade,physical exercise,drinking,monthly income per capita of the family were important influencing factors of PSQI.Conclusion Sleep quality was influenced by many factors.Measures such as arranging course reasonably,changing bad habit could be taken to improve sleep quality in medical students.