In order to understand the development trajectory, policy focus and policy exploration and adjustment direction of my country's medical security system, this research is based on grounded theory, with the help of NVivo12 software, using a combination of qualitative and quantitative methods to analyze the medical insurance related policies issued by various national departments from 2009 to 2020. The policy document takes the time when the National Medical Insurance Bureau was established in May 2018 as the dividing line, and is divided into two stages for open coding.The results show that after three-level open coding, 91 concepts and 26 categories were extracted from the policy texts from January 2009 to May 2018, and 92 concepts and 29 categories were extracted from the policy texts from June 2018 to December 2020.Comparing the open coding results of the two stages, and sorting and analyzing them from the category level and the conceptual level, it can be found that the average annual number of policy releases after the establishment of the National Medical Insurance Administration is 3.2 times that of the previous ones, mainly in the "supply-side reform of medical services", "medical security public management services" and "treatment guarantee mechanism" three areas have been greatly adjusted from before.