The effects of doping amount and particle size of alumina on the sintering behavior and electrical performance of 8 mol% yttria-stabilized zirconia (YSZ) are investigated through microstructure and impedance spectroscopy analysis. Initial results show that a proper amount of Al2O3 doping can effectively improve the sintering behavior and the electrical performance of YSZ, and the optimum doping amount varies with the particle size of Al2O3. When a raw Al2O3 powder (modal particle size: 028 mu m) is used as dopant, the optimal doping amount for electrical and sintering improvement is 0.7 wt.% and 3 wt%, respectively, while that with 1400 degrees C-calcined-Al2O3 (0.45 mu m), 1 wt.% and 4 wt.%. A concept of space distribution distance of the doping particles is introduced to interpret the improvement effect. (C) 2016 Elsevier B.V. All rights reserved.