Abstract: A performance analysis model of the gas lubricated compliant multileaf journal bearing of the high-speed rotor for air cycle machine of aircraft environmental control system has been established.In the analysis,the differential method is used to solve the compressible Reynolds equation,which governs the airflow in the journal bearing.The solution is coupled with the load deflection equations of the leaves to obtain such information as minimum film thickness, the stiffness coefficients,and the equivalent damping coefficients.The graphical solutions are provided for a range of relevant geometric and operational parameters.The journal bearing has good stability in all range of eccentricity ratios and all possible operating speeds.