The high-temperature oxidation resistance behavior of Pt-Al coatings prepared by the electroplating of platinum with the following pack cementation of aluminum on nickel-based superalloys GH586 was studied by SEM, XRD and EDS. The results show that high temperature oxidation resistance of the Pt-Al coatings is excellent. The addition of platinum can prevent the diffusion of the alloy elements in the superalloys outwards to surface layer, and thus increase the high temperature oxidation resistance of coatings. The operation mechanisms of platinum on oxidation behavior were also discussed