The mixture of Ni, Co, Cr, Al, Y powders were prepared by mechanically mixing method for 4 hours with the ratio of 4:2:1.5:1:0.03 of Ni, Co, Cr, Al, and Y, and the deposited mixed powder coating with a thickness of 150 μm was prepared on the 310s stainless steel substrate by using the low-pressure cold spray equipment (GDU-3-15). The sample was placed to a vacuum tube furnace (TL1700) for thermal diffusion treatment. The microstructure, phase composition and microhardness of in-situ synthesis NiCoCrAlY alloy coatings were analyzed by Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffractometry (XRD) and microhardness tester, et al. The results show that the mixed powder coating of Ni, Co, Cr, Al,Y prepared by the cold spraying is mainly constituted with simple elements. However, the diffusion reaction of the elements occurs in the coating after vacuum diffusion at 1100 ℃ for 4 h. Simultaneously, there is a diffusion phenomenon between the coating and the substrate, which forms an obvious metallurgical bond. Oxidation experiments show that the NiCoCrAlY coating of in-situ synthesis exhibited significantly lower oxidation weight gain than the pure substrate, which can protects the substrate from rapid oxidation effectively.