About 15 billion N m(3) coke oven gas (COG) is emitted into the air in Shanxi Province in China as air pollutants. It is also a waste of precious chemical resources. In this study, COG was purified respectively by four methods including refrigeration, fiberglass, silica gel, and molecular sieve. Purified COG was separated by a prism membrane into two gas products. One consists mainly of H-2 (> 90 vol %) and the other is rich in CH4 (> 60 vol %) with their exact compositions to vary with the membrane separation pressure and outlet gas flow ratio. The gas rich in CH4 was partially oxidized with oxygen in a high-temperature fixed-bed quartz reactor charged with coke particles of 10 mm size. At 1200-1300 degrees C, a CH4 conversion of > 99% could be obtained. The H-2/CO ratio in the synthesis product gas can be adjusted in the range 0.3-1.4, very favorable for further Cl synthesis.