Traditional research believes that the medical insurance system can allocate primary medical and health resources through graded diagnoses and treatments. However, due to differences in long-term regional development, China's medical insurance system is characterized by fragmentation, thus not only hindering the realization of equalization of medical and health resources but also intensifying the differences. This problem is particularly acute in the process of equalization of medical and health resources at the county level.

By examining the existing Chinese medical insurance integration model, we found that there are some problems in current medical insurance integration practices, such as insufficient guidance for residents to seek medical treatment, uneven benefits among groups, and uneven benefits among regions, thus making it difficult for medical insurance integration practices to play a guiding role in the allocation of county medical and health resources. Therefore, based on the theory of equal opportunity, this paper pays attention to the inequality of opportunity between individuals and regions and puts forward some suggestions regarding the integration of medical insurance with a high level of national security and regionally graded diagnoses and treatments.

In order to prove the feasibility of this theory, we use panel data from 38 counties from 2004 to 2016, taking the free medical care reform in Shenmu as an example and using the synthetic control method to analyze the role of medical insurance integration in guiding the allocation of medical and health resources at the county level from the perspective of equal opportunity. The empirical results show that: (1) from the perspective of equal opportunity, medical insurance integration can improve the number of beds per 10,000 people and the number of medical and health personnel at the county level; (2) from the perspective of equal opportunity, medical insurance integration has no significant effect on increasing the number of medical institutions per 10,000 people at the county level, and there are potential negative effects; (3) from the perspective of equal opportunity, the policy continuity of medical insurance integration is insufficient and the short-term effects are significant, with the policy effect gradually weakening over time.

On the whole, from the perspective of equal opportunity, at the county level medical insurance integration can guide the allocation of medical and health resources and promote the equalization of medical and health resources. However, it can only narrow the gap between counties and large and medium-sized cities in urban agglomeration by directly serving patients and thus a reasonable adjustment of medical insurance policies is still required.

In the future, medical insurance integration should pay attention to the substantive fairness of medical insurance integration and protect the interests of vulnerable groups. At the same time, it should promote reform of the existing graded diagnosis and treatment system and strengthen regional medical guidance. Furthermore, improvements in the management of financial subsidies and medical insurance funds are needed to cultivate momentum in the long-term construction of county medical and health care. Finally, through the system design to implement and strengthen the medical insurance referral function, private capital should be encouraged to enter the operation of public hospitals.