Method for preparing synthesis gas through coke oven gas and coal gas

The invention provides a method for preparing synthesis gas through coke oven gas and coal gas. The coke oven gas and the coal gas are fed to a gas holder to be fully mixed, mixed gas is obtained, methane reforming is conducted on one part of the mixed gas, reformed gas and the other part of mixed gas converge, and are compressed and then purified, H2S, remaining CO2 and other impurities are removed, removed hydrogen sulfide is desulphurized and recovered, removed CO2 is emptied, methane separation is conducted on purified coarse feed gas, liquefied natural gas products or compressed natural gas products are prepared through separated methane gas, and the pure synthesis gas meeting the requirement of the hydrogen-carbon ratio of synthesis downstream products is prepared through gas in which methane is separated. The method has the advantage that the coal gas and the coke oven gas are comprehensively utilized.