In order to reasonably utilize coke oven gas（COG）,first,a Lurgi gas-phase methanol synthesis system was designed,with COG as the raw material,and the key parameters of the system were obtained by the simulation with Aspen Plus.Next,the performance of gas-steam combined cycle firing COG was calculated and compared with that firing natural gas.Then,a parallel poly-generation system for gas-phase methanol synthesis and electric power generation was designed.Finally,a performance comparison was performed between the designed system and the exi-sting one-product system.The results show that the carbon supplementation before reformer increases the methanol yield and decreases the energy consumption by about 6%,that the net power and thermal efficiency of the combined cycle respectively decrease by 0.87% and 0.91% when substituting COG for natural gas,and that the thermal efficiency of the poly-generation system is about two points of percentage higher than that of the one-product system.Thus,it comes to the conclusion that the proposed poly-generation system with carbon supplementation before reformer is of the highest thermo-economic benefit.