Cermet coatings of NiCr-Cr ₃C ₂  were thermally sprayed on 304 sink roll by high velocity oxygenfuel spraying technique. The corrosion resistance of prepared sample was tested at 600 ℃ in a molten zinc-aluminum containing 55% of aluminum. The inactivation process of sink roll was studied. SEM was used to determine the morphology changes of initial powder and the sample after the corrosive experiment. EDS was used to determine the element composition of initial powder and the coating after corrosion. The data showed that the porosity, bonding strength and micro hardness were 2.9%, 82.76 MPa and 1 078.67 HV respectively before corrosion. While after 1 day's corrosion, NiCr in NiCr-Cr ₃C ₂  cermet was found to be dissolved in Zn, thus the protection ability of Cr ₃C ₂was lost.