The work aims to improve the high temperature and oxidation resistance of GH80A used in gas turbine blade. High-Current Pulsed Electron Beam (HCPEB) technology was applied to treat the surface of nickel-based superalloy GH80A. Microstructural evolution and oxidation behavior and mechanism at 850 ℃ of GH80A before and after HCPEB irradiation were investigated. The microstructure and oxidation products induced by HCPEB were characterized by optical microscope (OM), X-ray diffraction (XRD) and scanning electron microscopy (SEM). After HCPEB irradiation, the surface of GH80A alloy was melted apparently and a 3 μm thick remelted layer was formed. Besides, a large number of dislocation slips were formed in the remelted layer, and the crystal grains were clearly refined. From the results of high-temperature oxidation test at 85 ℃, after oxidation for 100 h, the initial sample had the largest oxidation weight gain and the oxide scale was rather thicker with a lot of cracks. The Cr2O3 was volatilized, so the oxide film was porous. The matrix appeared severe internal oxidation. After HCPEB irradiation for 20 times, the weight gain of sample was the smallest. The oxide scale was composed of TiO2 outer layer and Cr2O3 inner layer after 100-hour oxidiation. The continuous and dense TiO2 produced in the outer layer inhibited the volatilization of Cr2O3, so the Cr2O3 oxide film was continuous and dense without peeling and protected the substrate to some extent. After HCPEB irradiation, the high temperature oxidation performance of samples GH80 alloy is significantly improved. The high temperature oxidation resistance of 20-pulsed irradiated samples is the best.