The kinetics and density functional theory (DFT) of dimethyl ether (DME) synthesis from methanol dehydration over AlOOH catalysts prepared by complete liquid phase method in a slurry bed reactor was investigated. The kinetic model showed that the rate-limiting step of CH3OH dehydration over AlOOH catalysts was coadsorption of two methanol molecules. The process of DME synthesis from methanol dehydration over AlOOH(100) surface in liquid paraffin was also studied with DFT，and the reaction process and activation energy of the rate-limiting step were consistent with the kinetic model，further indicating that the model could reasonably describe the process of DME synthesis from methanol dehydration over AlOOH catalysts by complete liquid phase method.