The Pt and Hf modified γ-Ni+γ′-Ni3Al coatings were fabricated on the DZ417G superalloy substrates by combined aluminizing and hafnizing using a pack cementation. During the co-deposition process, the phase structure formed on the coating surface changes with the increasing of hafnium contents in packs. When the hafnium contents are 2 wt%, 6 wt% and 12 wt% the coatings consist of the γ-Ni+γ′-Ni3Al, b-NiAl+Al16Hf6Ni7, and Al16Hf6Ni7, respectively. During post heat treatment the β-NiAl+Al16Hf6Ni7 and Al16Hf6Ni7 coatings are transformed to γ-Ni+γ′-Ni3Al and γ-Ni+γ′-Ni3Al+Al3HfNi12. Isothermal oxidation tests at 1100 ℃ for 10 h show that there are a lot of spallation on the surface of the substrate without coating, while the Pt and Hf modified γ-Ni+γ′-Ni3Al coating formed in the packs with 2 wt% Hf remains to be integrated after being oxidized for 30 h. The addition of the reactive element hafnium makes a further improvement on the oxidation resistance of the Pt+γ-Ni+γ′-Ni3Al coatings