Objective: To study the relationship between the financial input and the supply level of medical and health services in 31 provinces in China from 2016 to 2021, and provide references for the rational allocation of financial resources in the medical field. Methods: The panel data was used to construct the evaluation index system, and the entropy method was used to calculate the index of medical and health service supply level in each province. Based on the dual-way fixed effect model, the effect mechanism of financial input on the medical and health service supply level was discussed. Results: The financial input has a significant positive impact on the improvement of the level of medical and health service supply, and the impact of the underdeveloped areas is greater than that of the developed areas; the financial operation efficiency has a significant positive regulating effect on the relationship be- tween financial input and the level of medical and health service supply; income inequality has a significant negative regulatory effect on the relationship between financial input and the level of medical and health service supply. Conclusion: It is needed to optimize the allocation of medical financial resources and increase financial investment; deepen the reform of the medical and health system and improve the operational efficiency; improve the social security system, and promote health and equity.