Abstract: The construction of medical and healthcare informatization is the focus of the new round of medical and healthcare system reform in China, and is also the technical basis to realize the modernization of medical and healthcare governance in China. However, the construction of medical and healthcare informatization is systematic and complex, which requires efficient cooperation and collaborative governance of multiple sectors. Based on the relevant documents issued at the national level since the new medical and healthcare reform ten years ago, the paper uses social network analysis to measure the node attributes of the collaboration network of policy subjects, and builds a two-dimensional matrix of the “breadth-depth” of the collaboration among policy subjects to analyze the evolution rules of the roles of different policy subjects in the collaborative governance of the construction of medical and healthcare informatization. The results show that the policy subjects are becoming increasingly diversified, and the collaborative relationship between subjects is increasingly complex, but the institutions that play the core role are limited, and the policy collaborative network is remarkably centralized. A closed loop of close collaboration has gradually been formed among the National Health Commission, the National Administration of Traditional Chinese Medicine, the National Development and Reform Commission, the Ministry of Finance, the Ministry of Science and Technology, the Ministry of Industry and Information Technology, the Ministry of Civil Affairs, the State Administration for Market Regulation, and the Ministry of Education. The change path of the roles of the policy subjects is mainly progressive, and the direct driving force for sudden evolution stems primarily from the promulgation of the key policy texts by the higher-level governments. Policy-oriented mechanism for learning and communication is an important prerequisite for building trust-based intergovernmental relations, promoting the collaboration among policy subjects, and realizing the modernization of medical and healthcare governance.