Both the construction of merged medical alliance and medical insurance payment reform are innovative measures of "taking residents' health as the center"，reflecting the guarantee of the system and the breakthrough of the mechanism. The 12 merged county medical alliances in Sanming City implement the combination of lump sum contracting and C-DRG collection and payment fees to achieve the "double package" of medical insurance payment. Through the analysis of the medical insurance payment reform and the relevant policies of the medical community，combined with the operating data of the 12 merged county medical alliances in Sanming City from 2017 to 2021，the impact of the medical insurance payment reform on the operation and management of the tight medical community were deeply evaluated by taking the medical insurance fund balance，the C-DRG implementation，hospital income structure，hospital staff income，average cost per visit，average length of stay，hospitalization reimbursement ratio and other indicators as the evaluation dimensions. On this basis，Yongan Medical Community with obvious decline in business volume but good results was taken as the research sample，to further explore the internal impact mechanism of medical insurance payment reform on the operation and management of merged county medical alliance，so as to put forward policy recommendations to optimize the operation and management of merged county medical alliances.