The invention discloses a centrifugal air compressor based on a hydrogen fuel cell engine. Comprising a shell, a positioning sleeve, a motor stator, a torque winding, a suspension winding, a rotor main shaft, a motor rotor, a thrust plate, a gas bearing part, a volute back plate, a compression volute, an expansion volute, a compression impeller and an expansion impeller, wherein the torque winding and the suspension winding are arranged on the motor stator; the rotor main shaft, the motor rotor and the thrust plate are integrally designed, so that the installation space and the installation procedure are saved, and a plurality of gas bearing grooves with the outer contours in the shape of hummingbird wings are formed in the two end faces of the thrust plate and the rotor main shaft. The torque winding and the suspension winding which are sequentially sleeved from outside to inside in the radial direction inside the motor stator provide rotary driving force and controllable radial suspension force for the rotor main shaft, so that the rotor main shaft realizes suspension work under all working conditions, the service life of the compressor is prolonged, power consumption is reduced, and the service life of the compressor is prolonged. And the requirements of small size, high speed, large flow and high reliability of the air compressor of the hydrogen fuel cell engine are met.