As the thrust-to-weight ratio of the aero-engine increases, the turbine inlet temperature increases significantly, leading to a significant increase in the service temperature of other key hot-end components. In the process of service, nickel-based superalloys need to withstand the combined effect of high temperature, stress and environment, and the alloy surface will inevitably occur high temperature oxidation. High temperature oxidation often preferentially penetrates along grain boundaries, resulting in micro-voids and micro-cracks at grain boundaries, which seriously affects the properties of the alloy. Therefore, it is necessary to explore ways to improve the oxidation resistance of alloys at high temperatures. In this work, the effect of Hf on oxidation behavior of K4800 nickel-based superalloy was studied. The results show that the oxidation weight gain of K4800 and K4800+0.25Hf alloys increases with the extension of exposure time during static oxidation at 800℃ and 850℃, and the oxidation kinetics curves follow the parabola rule. However, the initial static oxidation rate of K4800+0.25Hf alloy (0.0265 g/m2·h at 800°C for 20 h and 0.0617 g/m2·h at 850°C for 20h) is lower than that of K4800 alloy (0.041 g/m2·h at 800°C and 0.0669 g/m2·h at 850°C). The oxide layer of the two experimental alloys comprises an outer oxide layer and an inner oxide layer.The outer oxide layer primarily consists of dense Cr2O3, while the inner oxide layer mainly contains dendritic Al2O3. However, with the Hf content increasing from 0 wt.% to 0.25 wt.%, the thickness of the Cr2O3 outer oxide layer decreases from 2.71 μm to 2.17 μm after oxidation at 800°C for 1000 h and from 5.83 μm to 4.09 μm after oxidation at 850°C for 1000 h.The results of EPMA analysis indicate the formation of HfO2 at the grain boundary of the oxide layer in the K4800+0.25Hf alloy, promoting the formation of Al2O3 around HfO2 and accelerating the growth of Al2O3. The presence of Al2O3 and HfO2 at the grain boundary contributes to reducing the outward diffusion rate of Cr3+ and delaying the thickening of the Cr2O3 oxide layer. Consequently, the addition of Hf enhances the oxidation resistance of the K4800 alloy.