Abstract: The corrosion behavior of K465 alloy with NiCrAlY layer, K465 alloy with SiO₂/NiCrAlY composite coating and K465 alloy with Au/SiO₂/NiCrAlY composite coating under acidic salt spray environment were studied. SEM and EDS were used to observe the micro morphology and composition changes of the surface and cross-section of the samples before and after acid salt spray testing in three. The acid resistance and salt spray corrosion behavior of K465 alloy under different protective layer states were studied. The results indicate that the K465 alloy containing SiO₂/NiCrAlY complex coating has almost no corrosion, mainly due to the fact that SiO₂ coating on the surface of the NiCrAlY coating can significantly reduce the contact area between the corrosive medium and the NiCrAlY coating, thereby reducing the corrosion channels.K465 alloy with a NiCrAlY coating undergoes slight corrosion, mainly due to the inclusion of many active metal elements(such as Al, Cr, etc.)with low corrosion potential in the coating. The K465 alloy containing Au/SiO₂/NiCrAlY complex coating has the most severe corrosion, which is due to the formation of a galvanic cell structure between Au layer and NiCrAlY coating under the connection of the corrosive medium, thereby, the corrosion of the NiCrAlY coating are exacerbated.