NiO-μm and NiO-nm in SOFC anodes, which were prepared by tape casting, were compared. It was found that, the maximum power density of the cell with NiO-nm as anode was 257.1mW/cm2 at 800°C, but that was only 124.9mW/cm2 for NiO-μm. The reason was that the anode with NiO-nm has larger trible phase boundary. After calcining at 700°C for NiO-nm, the power density increased to 369.0mW/cm2, while it deceased to 169.5 and 159.0mW/cm2 at 800 and 900°C respectively, because NiO calcined at 700°C improved its activity and held its small particle size, but the particle increased abruptly up to 1.35μm at 800 and 900°C. When YSZ in the anodes calcined at 1200°C, the particle size increased from 0.2-34νm, the maximum power density of the cell decreased to 120.0mW/cm2, because NiO was isolated by large YSZ. However, these YSZ were milled for 12h, the particle size decreased to 0.70μm and the power density increased to 447.9mW/cm2 because of YSZ and NiO distributed uniformity.