In order to meet the requirements of long life, high reliability and low energy consumption for the vapor cycle cooling system（VCS） on aircraft in the future, the application of the quasitwo stage vapor cycle cooling technology in the aircraft environ mental control system is studied. The theoretical cycle and quasi-two stage compression process of the two stage compression refrigeration cycle are analyzed, and then the performance of the theoretical cycle and product performance are test. They are proved that the quasitwo stage compression cycle is used instead of singlestage compression cycle, under the vaporliquid heatexchanger, the coefficient of performance (COP) value of the system is increased by 29%. At the same time, the compressor speed decreased by 38%, the discharge temperature decreased by 29%. Correspondingly, the working life and reliability of the compressor are greatly improved.