Objective: Patients with acute pancreatitis from 2019 to 2021 in a tertiary hospital in Zhejiang Province were included in the study to evaluate the changes in patient hospitalization costs before and after the DRGs reform, aiming to provide empirical evidence for the continuous optimization of the policy. Methods: The interrupt time series model was used to analyze the trend of hospitalization costs before and after the implementation of the policy, and Spearman correlation analysis was used to explore the correlation between the total hospitalization costs and the costs of each component. Results: The analysis showed that the total hospitalization cost increased by 1639.3 yuan per month before the reform (P < 0.001), decreased by 1924.1 yuan per month after the reform (P < 0.001), and the drug cost and medical service fee decreased by 910.0 yuan and 480.3 yuan per month, respectively (P < 0.001). After the reform, the medical service fee showed the strongest correlation with the total hospitalization cost (r=0.941, P < 0.001). Conclusion: The study found that with the implementation of DRG reform, the hospitalization cost of acute pancreatitis patients in the sample hospital decreased year by year, indicating that the reform effect was significant. Medical institutions responded effectively to the policy change by strengthening the control of drugs and consumables and standardizing medical behavior. In order to further enhance the regulatory role of DRG policy, it is suggested to adjust the price of medical service to motivate medical personnel, and establish a dynamic adjustment mechanism to optimize the DRG grouping scheme to ensure that the policy better meets clinical requirement and medical practice.