In this study, mesoporous titania/alumina membranes were prepared by sol-gel method. Pore structure and phase composition of titania/alumina membranes could be changed by calcination temperature. The addition of alumina into titania membranes retarded anatase-to-rutile phase transformation, resulting in stabilization of pore structures. The 5 time dip-coated membrane calcined at $450^{circ}C$ is about $10.3{mu}m$ in thickness with an average pore size of 5 nm. Hydrogen and nitrogen permeances through the membrane were $17.1{ imes}10^{-7}mol/m^2{cdot}s{cdot}Pa$ and $4.7{ imes}10^{-7}mol/m^2{cdot}s{cdot}Pa$, respectively. These data were explained by the Knudsen diffusion mechanism.