The oxidation behaviors of FeCrNiAl high entropy alloy at high temperature were investigated in this paper, and the oxidation kinetics model was constructed. The phase structure, morphology and composition were characterized by XRD, SEM and EDS, and the oxidation mechanisms were analyzed. The results show that the alloy are all oxidation-resistant at 800-1000℃, the average oxidation rate in unite area in 100h increases with increasing temperature at first, then decrease and the average oxidation rate at 1000℃ is smaller than at 800℃.The relationship between weight increment in unite area and oxidation time for all temperatures meets parabola function, and the oxidation active energy was calculated to be 167.507KJ/mol. The oxidation products in dendrite at 800℃ are bar-shape TiO2 with rutile structure, while the interdendritic products are Cr2O3 and TiO2 which show plate shape. The oxidation products at 900℃ are TiO2, Cr2O3 and Fe2O3, while TiO2 and α-Al2O3 are observed at 950℃. Only tight α-Al2O3 film are gotten on the surface at 1000℃, which results in the more excellent oxidation-resistant property.