Objective To study the high temperature gas corrosion resistance of NiCoCrAlY coating. Methods The NiCoCrAlY coating was prepared by high-energy and high-speed plasma-spraying technology on Ni3Al based alloy IC6. The adhesion strength and gas hot-corrosion kinetic curve of IC6 and coating at 900 ℃ were tested. The microstructure and phase composition of the coating before and after corrosion test were also analyzed by means of SEM and XRD. Results The NiCoCrAlY coating which was prepared by high-energy and high-speed plasma-spraying had high density with the porosity no more than 3%. The combination between coating and substrate was in good condition, of which the average adhesion strength reached 62 MPa, and the content of oxide and inclusion in the coating was little. The corrosion rate of the IC6 alloy and the coating was respectively 8.09 g/(m2?h) and 0.50 g/(m2?h) after 100 h‘ gas hot corrosion. Conclusion The gas hot-corrosion resistance of IC6 alloy has been increased significantly by applying NiCoCrAlY coating. The surface of coating has produced complete and compact oxide film, with Al2O3 and Cr2O3 as the main component. Al2O3 has good oxidation resistance and Cr2O3 has good corrosion resistance. Under the influence of both, the erosion of the corrosion atmosphere towards internal coating has been blocked and delayed. At the same time, because of the little defects such as pores and oxidation in the coating, the diffusing passageway of the corrosion atmosphere has been separated and the corrosion rate has been decreased, which has resulted in a good protection for IC6 alloy.