Objective: Under the background of DRG payment, the paper compares the hospitalization cost structure changes of hip and knee joint replacement patients before and after the implementation of centralized procurement policy, to provide references for evaluating the effectiveness of artificial joint centralized procurement. Methods: Hip and knee joint replacement surgery patients under the DRG group of IC29 were included as samples. The patients' basic information, hospitalization information, and medical cost data were collected, distinguishing the two stages before and after the centralized procurement. The descriptive statistical analysis, chi-square test, Mann-Whitney U test, and degree of structure variation analysis were employed. Results: Patient's hospitalization days significantly decreased after centralized procurement policy (P<0.05). Centralized procurement had significant impacts on patients' total hospitalization costs, medical service costs, drug costs, and consumable costs (P<0.05), and the corresponding median values decreased by 25261.12 yuan, 1069.04 yuan, 849.24 yuan, and 8299.53 yuan, respectively. The contribution rate of the structural changes of the consumables costs, medical services costs, and inspection costs was 50.00%, 28.37%, and 12.13%, respectively. The median value paid by the medical insurance fund and individuals decreased by 2283.98 yuan and 12729.65 yuan, while the median value of DRG payment increased by 1274.45 yuan. Conclusion: Under the centralized procurement of artificial joint and DRG payment, the structure of hospitalization cost of hip and knee joint replacement surgery patients is optimized, the inpatient medical burden of patients is reduced, and the medical insurance fund is used more efficiently.