Oxy-fuel (alcohol，DME，etc.) is the main chemical product of the coal-based polygeneration system.In this system，25%(vol)methane in the coke-oven gas is reformed with 23%（vol）CO2 in the gasified gas，and the syngas at a proper H/C ratio is further changed to oxy-fuel.It is a system with energy-saving and friendly environment.The synthesis of oxy-fuel is the key unit for determining the efficiency and economics for the polygeneration system.In this study，Aspen Plus software was employed to establish an integrated coal-based polygeneration flowsheet.In the simulation，the equivalent yield of methanol and conversion of CH4 and CO2 were used as the objective functions for optimizing the operation parameters in the whole polygeneration system.Furthermore，the synergetic effect in the one-step DME synthesis process was investigated.