Different samples of mesoporous nano-sized γ-alumina were prepared through surfactant-free sol-gel process, using aluminum nitrate as precursor. The influence of variables such as addition of alcohol, metal salts and also effect of changing the aluminum source were investigated on the synthesis method. The products, which were obtained on different conditions, were then characterized by XRD, FT-IR, SEM, TEM. Moreover, textural properties were also measured by BET. To study thermal stability of prepared alumina; Cerium nitrate, magnesium nitrate, lanthanum nitrate and gadolinium nitrate were added as dopants. The catalytic performance of the synthesized mesoporous alumina (with a surface area of 272 m2/g, pore volume of 0.94 cm3/g and pore size of 13.8 nm) was studied for the methanol conversion to dimethyl ether, and the result was compared by commercial γ-alumina. Synthesized mesostructured catalyst has comparable activity and DME selectivity at 300°C to that of commercial alumina at 400 °C.