The influence of temperature, pressure and initial molar ratio of substrates on the equilibrium conversion degrees in direct synthesis of dimethyl ether (DME) from CO and H-2 has been established. The significant influence of the temperature on the equilibrium content of the product has been found. Modelling results have shown that the one-step synthesis of DME from CO and H-2 in higher pressures and relatively lower temperatures (T < 550 K) is beneficial because of the high selectivity and yield of the main process product.