Compared to methane and methanol, dimethyl ether seems to be a superior candidate for high quality diesel fuel in the near future. To meet the continuously increasing global requirements, a larger scale reactor is needed to produce more dimethyl ether. A heterogeneous one-dimensional model was developed to simulate a staged adiabatic fixed bed reactor for the catalytic dehydration of methanol to dimethyl ether. To verify the proposed model, the simulated catalyst bed temperature has been compared to available data from an industrial reactor. A good agreement has been found between the simulation and plant data. Also, the effects of some operational parameters, such as feed flow rates, the inlet temperatures of methanol, pressure, and catalyst particle diameter on reactor behavior were investigated. The simulated results show that this model is reasonable and reliable.