Objective: Taking a tertiary public hospital in Tianjin as an example, to sort out the internal mechanism of the influence of the total budget management mode of regional points method on medical expenses, and to deeply study the effect of the adaptive management measures to be taken by medical institutions on cost control under the background of reform. It provides references for optimizing hospital management measures and development path. Methods: Based on CIMO framework, the overall situation of total budget management policy of regional points method in Tianjin was analyzed, and the system structure of the impact of reform on medical cost control in public hospitals was presented. Based on the system dynamics theory, the SD model of public hospital cost control under the method of regional points was further constructed. Different management measures were selected as targets and interventions were carried out to quantitatively study the control situation and development trend of medical expenses in medical institutions. Results: After targeted intervention, cost accounting, performance assessment, information construction, path standardization and medical record quality control, the decreasing trend of the amount of medical expenses and the actual burden of patients was strengthened to a certain extent, and the influence on the latter was stronger. Among them, information construction, path specification, cost accounting has a greater impact. Conclusions: Strengthen the consensus and cooperation of multi-department management, innovate the work flow and timely data feedback analysis, and adjust the performance management plan of medical staff according to the related indicators of medical insurance.