The new high surface area and high active nano-sized porous -Al2O3 catalyst was produced by a co-precipitation method. The synthesized catalyst was characterized by X-ray diffraction, Fourier transform infrared, NH3-temperature programmed desorption, and Brunauer-Emmett-Teller techniques. The results of characterization tests showed excellent textural and acidic properties of the synthesized catalyst for the methanol dehydration reaction. Catalytic dehydration of methanol to dimethyl ether was performed in an adiabatic fixed bed reactor using the new nano-sized catalyst at different operating temperatures. The results showed that the highest methanol conversion occurs in the temperature range of 300-350 degrees C. Finally, a new correlation was developed to predict methanol conversion from operating temperature.