NbOx is added in Ni-Ce0.8Sm0.2O1.9 by impregnation as an anode material for solid oxide fuel cells fed with methanol. Nb (IV) and Nb (V) exist in the reduced anode. The addition of Nb reduces the binding energy of Ni. The catalytic activity of the anode and the performance of the single cell both increase with the increase of Nb. At 700 °C, the cell with 5NbOx-Ni-Ce0.8Sm0.2O1.9 anode and Ce0.8Sm0.2O1.9-carbonate electrolyte shows a output power density of 687 mW cm−2. Meanwhile, water produced in the anode is absorbed by NbOx and forms surface hydroxyl groups, which facilitates the removal of carbon. The addition of NbOx decreases the amount of deposited carbon in the humidified methanol atmosphere significantly, and an improved stability of the single cell is achieved.