The invention relates to a two-stage series pressurization direct-driven centrifugal air compressor of a fuel cell engine. The two-stage series pressurization direct-driven centrifugal air compressor comprises end covers, a spindle, volutes, impellers, a rotor, a stator and a driver. The spindle is supported by a left-end radial supporting air foil bearing, a left-end radial supporting air foil bearing bush, an air foil axial thrust bearing and a right-end radial supporting air foil bearing, wherein the left-end radial supporting air foil bearing and the left-end radial supporting air foil bearing bush are arranged on the left side, and the air foil axial thrust bearing and the right-end radial supporting air foil bearing are arranged on the right side of the spindle. The left-end radial supporting air foil bearing bush is arranged on the outer side of the spindle in a surrounding manner. The left-end radial supporting air foil bearing is fixed to the outer side of the left-end radial supporting air foil bearing bush. The air foil axial thrust bearing is fixed to the outer side of the spindle in a bush form. The right-end radial supporting air foil bearing is fixed to the outer side of the air foil axial thrust bearing. Compared with the prior art, the two-stage series pressurization direct-driven centrifugal air compressor is more suitable for the air inlet pressurization scene of the fuel cell engine with the high oilless air inlet requirement, and the durability and reliability of the air compressor of the fuel cell engine can be improved.