Objective: The paper intends to provide empirical data for DIP reform by analyzing the basic situation, diagnosis and treatment situation, and changes in hospitalization cost of patients with acute upper respiratory tract infection before and after DIP reform in sample hospitals. Methods: The relevant information of the first type of acute upper respiratory tract infection patients admitted to a pediatric hospital in Zibo City from July 2019 to June 2023 was collected. According to the actual implementation time of DIP in Zibo City, the patients were divided into pre-reform group and post-reform group, and the basic information was analyzed by Chi-square test. The difference between groups was analyzed by Mann-Whitney U test. Grey correlation analysis and structural variation were used to analyze the changes of total inpatient expenses and expenses of sub-items. Results: After the DIP reform, the age group of patients, the number of days in hospital and the stratification of hospitalization expenses changed. After the reform, the general medical service fee replaced the western medicine fee as the most relevant factor of hospitalization cost. The total structural change of inpatient cost of acute upper respiratory tract infection was 52.30%, and the top three factors influencing the positive structural change of inpatient cost were laboratory diagnosis cost, treatment disposable material cost, and non-surgical treatment cost. The top three factors influencing the negative structural change of hospitalization cost structure were clinical diagnosis cost, inspection disposable material cost, and western medicine cost. Conclusion: The reform of DIP payment mode can reduce the number of days of hospitalization, reduce the hospitalization cost and improve the structure of hospitalization cost to a certain extent, but it still needs to be further optimized.