Energy-saving transformation of existing buildings is the internal requirement of promoting ecological civilization city construction and realizing the 3060 "dual carbon goal", and its orderly development cannot be separated from the effective guidance of government decision-making. From the perspective of market operation,the theoretical research results of EPC mode, incentive policies, energy saving technology, transformation strategy and other aspects at home and abroad are summarized. Based on the perspective of decision making, the research achievements of project decision making theories are summarized from six aspects, including decision method, decision mechanism and decision optimization. Summarized the existing domestic and foreign building energy efficiency renovation market operation characteristics. In view of the lack of theoretical research on existing building energy conservation renovation at home and abroad, the particularity of government decision-making of existing building energy conservation renovation project is analyzed by comprehensively considering the advanced concept of existing building energy conservation renovation project, the overlapping of use and renovation, and the consideration of maintenance and improvement. The theoretical significance and practical value of government decision-making mechanism research on existing building energy conservation renovation projects are analyzed.