Objective:To evaluate the medical service quality of psychiatric hospitals in Beijing based on diagnostic related group (DRG), analyze the evaluation effect, for refences to constructe a DRG performance evaluation system suitable for psychiatric hospitals.Methods:This study extracted data such as the number of DRG groups, etc. of hospitalized patients in 14 tertiary and secondary psychiatric hospitals in Beijing from 2018 to 2020 from the Beijing inpatient medical performance evaluation platform, and analyzed data on DRG performance evaluation indicators, as well as the average length of hospital stay and average cost of DRG enrolled cases. All data were analyzed using descriptive research methods, and inter group comparisons were conducted using the Mann Whitney U-test. Results:From 2018 to 2020, the average number of DRG groups in tertiary hospitals (28) was higher than that in secondary hospitals (10) ( P<0.05), and the average CMI values of both were the same(1.79); The average cost consumption index (1.15) of tertiary hospitals was higher than that of secondary hospitals (0.65) ( P<0.05), while the average time consumption index (1.11) was slightly lower than that of secondary hospitals (1.30); The mortality rate of the low-risk group in tertiary hospitals (0.01%) was generally lower than that in secondary hospitals (0.88%), and the average percentage of DRG admitted inpatients (82.8%) was significantly higher than that in secondary hospitals (27.3%) ( P>0.05). The average length of stay and cost per case for DRG enrolled inpatients in tertiary and secondary hospitals were lower than the overall hospital discharge cases ( P<0.05). Conclusions:The number of DRG groups, CMI value, and low-risk mortality rate could be used for evaluating the medical service capacity and safety of psychiatric hospitals, but the cost and time consumption index could not objectively reflect the efficiency of hospital medical services. DRG performance evaluation indicators are more suitable for evaluating short-term hospitalization of psychiatric patients. The proportion of DRG enrolled cases might be a potential indicator for evaluating the service quality of psychiatric hospitals.