Thermodynamic analysis of single‐step synthesis of dimethyl ether (DME) from syngas over a bi‐functional catalyst (BFC) in a slurry bed reactor has been investigated as a function of temperature (200–240°C), pressure (20–50 bar), and composition feed ratio (H2/CO: 1–2). The BFC was prepared by physical mixing of CuO/ZnO/Al2O3 as a methanol synthesis catalyst and H‐ZSM‐5 as a methanol dehydration catalyst. The three reactions including methanol synthesis from CO and H2, methanol dehydration to DME and water–gas shift reaction were chosen as the independent reactions. The equilibrium thermodynamic analysis includes a theoretical model predicting the behaviour and a comparison to experimental results. Theoretical model calculations of thermodynamic equilibrium constants of the reactions and equilibrium composition of all components at different reaction temperature, pressure, and H2/CO ratio in feed are in good accordance with experimental values.