Abstract: Based on the experiment of absorption and distillation of dimethyl ether (DME)，the separation process for high purity DME was proposed for the one-step synthesis of DME from syngas. The gas mixture of condensed one-step reaction resultants was absorbed by deionized water，and the mixture stream of liquid from absorber and liquid stream of condensed one-step reaction resultants was fed into the DME rectifyer. DME was drawn from the side stream of the DME rectifier. The bottom stream containing water and methanol was then fed into the methanol rectifyer. With the experimental data，simulation calculation of the separation process was made for reference.