NiAl intermetallic compounds attract increasing attention for high-temperature applications due to their combination of excellent properties, especially as metallic protective coatings on superalloys or as bond coats in thermal barrier coatings(TBCs). Oxidation behaviour of the β-NiAlHf coatings prepared by electron beam physical vapour deposition(EB-PVD) was investigated at 1100 ℃ for short time and 100 h in 20 % O_2+Ar and 15% H_2O + Ar, respectively. The results of mass changes reveal that the addition of minor reactive element Hf significantly improves the cyclic oxidation resistance of the β-NiAl coatings in both dry and humid atmospheres. During the initial oxidation stage, water vapour retards the phase transformation from θ-Al_2O_3 to α-Al_2O_3. Moreover, compared with the case in dry atmosphere, water vapour significantly reduces the surface roughness of the oxide scales formed on EB-PVD β-NiAlHf coatings after 100 h cyclic oxidation, which corresponds with the difference of surface morphologies of the oxide scales. NiAl intermetallic compounds attract increasing attention for high-temperature applications due to their combination of excellent properties, especially as metallic protective coatings on superalloys or as bond coats in thermal barrier coatings (TBCs). Oxidation behavior of the β-NiAlHf coatings prepared by electron beam Physical evaporation (EB-PVD) was investigated at 1100 ° C for short time and 100 h in 20% O_2 + Ar and 15% H_2O + Ar, respectively. The results of mass changes reveal that the addition of minor reactive element Hf significantly improves the cyclic oxidation resistance of the β-NiAl coatings in both dry and humid atmospheres. During the initial oxidation stage, water vapor retards the phase transformation from θ-Al 2 O 3 to α-Al 2 O 3. significantly reduces the surface roughness of the oxide scales formed on EB-PVD beta-NiAlHf coatings after 100 h cyclic oxidation, which corresponds with the differen ce of surface morphologies of the oxide scales.