Objective: Based on the DRG official billing information, we analyzed the cases and costs of obstetric system, and evaluated the performance of each obstetric department to provide a basis for hospital refinement management. Methods: Based on the Beijing version of the CHS-DRG subdivision grouping scheme (version 1.1, ICD 2.0), the cost analysis was performed on the grouping payment results of 1468 patients who were included in the actual DRG payment from March 15, 2022 to July 31, 2022 in a grade 3A obstetrics and gynecology specialty hospital in Beijing. The DRG group number, case mix index (CMI), cost consumption index and time consumption index were used to evaluate the hospital's obstetric system medical service performance. The cesarean section cases, which were not included in the actual DRG payment, were analyzed by DRG. Results: (1) A total of 10 DRG groups were admitted to our obstetrics department with a CMI of 0.136. (2) Among the 10 DRG groups, 4 groups of OC19, OD19, OF29 and OS29, had a sub-average cost higher than the city average. After billing by DRG, 3 groups of OC19, OD19 and OS29, had a negative balance, with group OC19 having the largest deficit. (3) There were 6 departments in our obstetrics department, among which the CMI values of Department A, D, E and F were higher than the hospital average. The time consumption index and cost consumption index of Department A and C were less than 1, with the highest efficiency. (4) For cesarean patients paid by fixed amount, if paid according to DRG standard, the balance of each department was significantly higher than before. For patients with cesarean sections paid fee-for-service, when paid at the DRG rate, all departments made a loss, except for Department A, which has a slight average surplus, with an average loss up to 932.32 yuan. Conclusion: Through DRG payment, the obstetrics department of our hospital can be compared with the city's average cost, which is conducive to hospital fine management. Using DRG indicators to evaluate the performance of each department can objectively and fairly evaluate medical capacity and efficiency of each department, and help improve the quality of departmental services.