Abstract: The foreign advanced civil airplane cabin refrigeration system has been developed from three-wheel-bootstrap to four-wheel-bootstrap high pressure water-separation system. The traditional method used for matching the system thermal parameters was complicated. A new model for calculating the enthalpy parameters was proposed and used for the matching calculation. The gas flow ratio, fan power ratio and the turbine power ratio were introduced and their effect on system performance was analyzed. The results show that the use of enthalpy instead of temperature as the state parameter of the system accessories is of a clear physical concept, and can be easily programmed and avoid double counting of the saturated humidity of the connection points between accessories, and can also simplify the heat exchanger thermodynamic calculation and reduce the iteration times of the system. The results can provide a theoretical guidance for civil aircraft researches.