Abstract: Supercritical carbon dioxide cycle power generation technology is in the transition stage from model machine trial production to industrial application. Exploring and establishing a basic commissioning process suitable for new high parameter and large capacity CO2 boilers plays an important role in promoting the landing and transformation of relevant technical achievements. Taking the world's first 5MW supercritical carbon dioxide cycle power generation test unit as the research object, this paper comprehensively introduces the technical characteristics of the new boiler, and expounds its key commissioning process from the aspects of chemical cleaning, steam blowing and temperature adjustment. After debugging and adjustment, the test unit runs smoothly, and all parameters basically reach the design value, and the 72h joint test run is successfully completed. The relevant capital construction commissioning experience has important reference significance for the follow-up units of the same type.