Objective: The paper analyzes and compares the changes in the admission of relevant cases before and after the implementation of the "same disease and same price" policy in a tertiary comprehensive hospital in Shandong Province, and evaluates the effect of the policy in tertiary comprehensive hospitals. Methods: We obtain the medical insurance settlement list information and DRG enrollment information of cases included in the DRG basic disease group of a tertiary comprehensive hospital in Shandong Province in 2023, and uses descriptive statistical analysis, non-parametric testing and other statistical methods to statistically analyze the data before and after policy implementation. Results: Before and after the implementation of the policy, the number and proportion of cases admitted to the basic disease group in the sample hospitals significantly decreased, and the medical cost management effect of the basic disease group was significant, promoting the improvement of the efficiency of medical insurance fund utilization and the reduction of patient cost burden. At the same time, the hierarchical diagnosis and treatment of basic disease groups has effectively optimized the hospital's disease category structure. Conclusion: The basic disease group payment policy has positive significance in promoting the implementation of hierarchical diagnosis and treatment, reducing disease costs, and strengthening functional positioning in tertiary hospitals.