In the present work, an optimization has been performed on the effective operating parameters of dimethyl ether production. Dehydration of methanol to dimethyl ether was investigated in an adiabatic fixed bed reactor using an acidic.-alumina catalyst. A statistical experimental design method (an L9 orthogonal array Taguchi design) was applied to formulate the experimental layout and optimize the operating condition by considering temperature, pressure, and space velocity as the key parameters affecting the dimethyl ether yield. The experiments were conducted at the temperature range of 250390 C under pressures of 1-3 atmosphere and WHSV of 15 to 45 gr.h(-1)/gr(cat). The effect of each parameter is studied on the selectivity and methanol conversion trends. The results indicated that temperature and space velocity were the most significant controlling factors in order of importance. The presence of interactions and influence of them on reaction progress were also studied. Based on the analysis results, pressure interacted considerably with space velocity. The experiments revealed that the optimal operating range was at temperatures of 290-350 degrees C and space velocities of 15-30 gr.h(-1)/gr(cat), in which the maximum conversion was observed at a temperature of 310 degrees C and WHSV of 15 h(-1).