The invention relates to a thrust foil dynamic pressure air bearing with a thick top layer foil structure. The thrust foil dynamic pressure air bearing comprises a bottom plate (1), supporting wave foils (2) and top foil sheets (3), wherein the round bottom plate (1) are arranged on the lower part, the plurality of fan-shaped top foil sheets (3) are fixed above the bottom plate, and the supportingwave foils (2) are assembled on the bottom plate (1) and the top foil sheets (3); the bearing is characterized by further comprising inlet section gaskets (4) are arranged on one side in the radial direction of the joint of the top foil sheets (3) and the bottom plate (1), and the thickness of the inlet section gaskets (4) is adjustable; and the thickness of the top foil sheets is 0.5 mm to 1 mm,the support wave foils (2) and the top foil sheets are assembled in a pre-tightening mode, and the shape variable of the supporting wave foils is 0.01 mm-0.02mm. On one hand, the requirement for theconsistency precision of the foil bearing on the support wave foils is lowered, and meanwhile, the problem of foil deformation of the inlet sections of the top foil sheets of the thrust bearing is solved, so that the thickness shape of the gas film of the inlet section is basically unchanged, and the bearing capacity of the bearing is improved.