The bump foil dynamic gas bearing was developed for the hydrogen fuel cell centrifugal air compressor with a rated power of 26 kW and a spindle diameter of 22 mm.The static and dynamic characteristics experiments and durability experiments of the bearings were carried out on the built experimental bench,and the bearing hysteresis curves and static stiffness curves were obtained,as well as the three-dimensional spectrum diagram of the air compressor rotor system’s acceleration and deceleration vibration,and the time domain diagram from 30 000 r/min to 95 000 r/min.The experimental results show that there exits a nonlinear characteristics between the static stiffness and the displacement of the bearing.After more than 100 000 times of starts and stops of the air compressor,there is only slight wear on the surface of the flat foil,and there is almost no change in the height of the bump foil,indicating that the bearing has good durability.The rotor vibration is mainly on the fundamental frequency,the main amplitude is about 1 μm in the full speed range,and there was no obvious low-frequency and high-frequency vibration.The maximum stable speed of the two-stage air bearing centrifugal air compressor can reach 95 000 r/min,and it exhibits good thermal performance.