Abstract: A ferrous-nickel-based cermet inert anode was prepared by means of hot-pressing with a size up to D150 mm × 20 mm to apply to a 100 A electrolysis testing for 24 h at 900°C. In the whole electrolysis process the cell voltage was steady, which manifests that the anode is good at electrolytic conduction. According to the SEM results of the anode after electrolysis, it was found that the anodic corrosion due to electrolyte includes two processes. One is the reoxidation reaction between the oxygen ions produced from the anodic discharging of AlxOyFz^(2y+z-3x)- ions and the metal in anodic substrate, which causes the metallic oxides to be dissolved in electrolytic molten salt. The other is the anodic deposition of AlF3 into gaps, which is produced from the anodic reaction. A conclusion is thus drown that the coefficient of the anodic corrosion layer is different from that of anodic substrate and such a difference will result in the delamination even peeling off of the surface of anode in the cooling process. The corrosion rate is evaluated as 18 mm/a.