The surface fractal dimension, D, and pore size distribution of perovskite-doped alumina membrane prepared via the sol-gel method were determined from their nitrogen adsorption isotherms. The D value was calculated using the Frenkel-Halsey-Hill method. The D value increased with increasing temperature due to membrane shrinkage. The pore size distribution pattern of perovskite-doped alumina membrane showed a narrow pore size when the temperature was increased from 400 degrees to 800 degrees C. The isotherm type was characterized as Type IV. Smoothing and sintering effects contributed to the decreasing trend of surface fractal dimension at a high temperature. The surface fractal dimension increased when the perovskite ratio in alumina membrane was increased.