The hot corrosion behaviors of pure Ni, Ni-10Cr alloy and Ni-10Cr-5Al alloy (mass fractions, %, similarly hereinafter) coated with salt film of 75%Na2SO4+25%NaCl (mass fraction) were investigated at 900 °C in air. Results show that the corrosion kinetic curve of Ni-10Cr approximately follows the parabolic rate law while the corrosion kinetic curves of Ni and Ni-10Cr-5Al alloy follow the parabolic rate low by stages. The corrosion mass gain of Ni-10Cr is minimum, the one of Ni-10Cr-5Al comes next and that of pure Ni is maximum. The corrosion products of Ni-10Cr-5Al can be divided into three layers, of which the outermost layer is mainly composed of NiO, the intermediate layer consists of Cr2O3 and Al2O3 , and the internal corrosion zone contains a small amount of Cr2S3 and Al2S3. For Ni-10Cr alloy, the corrosion products consist of three layers, the outermost layer of NiO, the intermediate layer of noncontinuous Cr2O3 and the internal corrosion zone with a small amount of Cr2S3. The corrosion scales of Ni-10Cr-5Al and Ni-10Cr are both loose and porous due to the existence of NaCl.