The invention relates to a treatment method of improving oxidation resistance of a thermal barrier coating, belonging to the technical field of thermal barrier coating surface treatment and modification. High current pulse electron beam irradiation is utilized to realize electron beam physical vapor deposition to prepare a yttrium oxide stabilizing zirconium oxide thermal barrier coating to cap ceramic layer columnar crystals, thus the heat-shielding performance and the high temperature oxidation resistance of the coating are improved. The process conditions are shown as follows: the vacuum is 3.5*10<-2>Pa, the voltage is 15kV, the frequency is 1Hz, the pulse width is 120-150ms, the energy density is 10J/cm<2>-20J/cm<2>, the pulse time is 30-40 and the remelting layer thickness reaches at least 10 micrometers. The invention has the advantages that the electron beam physical vapor deposition layer columnar crystals are capped after the high current pulse electron beam irradiation is ended, and thus, the surface of the thermal barrier coating becomes smooth, no penetrable microcracks are generated, the oxygen element diffusion is effectively stopped, the growth of a thermal growth oxidation layer is relieved and the heat-shielding performance and the high temperature oxidation resistance of the thermal barrier coating are obviously improved.