Abstract: The gas lubricated compliant multileaf journal bearing of the high-speed rotor for air cycle machine of aircraft environmental control system was investigated experimentally.In the earlier work,an analysis model was developed to predict the performance of the air lubricated compliant multileaf journal bearing.In the experiments,the load deflection tests revealed the elastohydrodynamics of the compliant leaves;the starting torque tests found out the frictional influence between leaves and journal;the air cycle machine operational tests demonstrate the dynamic characteristics of the journal bearing.All of the experimental results show that the journal bearing can run steadily in wide operating range,and it has excellent static and dynamic performance.It is insensitive to environmental conditions.