The microstructure and oxidation resistance of NiAlHf and NiAlHfY coatings were systematically investigated at 1200 °C in air. The results revealed that Hf-rich oxides, Y-rich oxides, (Hf, Y)-rich oxides distributed at grain boundaries of oxide scale for NiAlHfY coating, which improved the adhesion and spallation resistance of oxide scale. And oxidation weight gains of NiAlHf, NiAlHfY coatings were 2.2425 and 1.8231 mg cm−2, respectively, which was reduced by 18.7% after Y-doping. The enhanced oxidation resistance was attributed to better synergistic effect of Hf and Y impeding ions diffusion. Finally, the Y-doping mechanism responsible for enhanced oxidation resistance was discussed.