Abstract: The hot corrosion resistance of CoCrAlSiY coating with different Si concentrations (0%, 2% and 5%) at 900 ℃ was discussed by using hot salt coating method with a mixed salt of 75wt% Na2SO4+25wt% NaCl. The CoCrAlSiY coating was prepared by HVOF method. The results show that the average corrosion penetration depth of coating increases with the rising temperature, while the increasing Si concentration decreases the average corrosion penetration depth of coating. Furthermore, CrSi, a high melting point metal silicide, is generated inside the CoCrAlSiY corrosion coating. Thus it is beneficial for improving the corrosion resistance of coating.