Objective:To analyze the impact of National Essential Drug System on residents' subjective well-being, and put forward targeted policy suggestions. Methods: Differences-in-Differences method is used to evaluate the overall effect and group differences of the implementation of National Essential Drug System. Results: The implementation of National Essential Drug System significantly promoted residents' subjective well-being. Furthermore, the impact varies greatly among some different groups. Conclusion: It is necessary to adhere to and strengthen National Essential Drug System's role orientation as "an important part of basic public services in the medical and health field", reduce the drug burden of patients with chronic or serious health problems, and effectively increase the proportion of essential drugs used by urban patients.