A process for preparing liquefied natural gas through coke oven gas includes the steps of directly conducting the three-section sulfur tolerant methanation reaction on a load type molybdenum-based sulfur tolerant methanation catalyst after oil, naphthalene, benzene and other impurities are removed from the coke oven gas, removing sulfur, CO2, C2-4 hydrocarbon and other impurities at a time through low temperature methanol washing, and finally obtaining the liquefied natural gas with the methane content as high as more than 97% after separating out N2, H2 and the like through one time of cryogenic liquidation. The process has the advantages of being simple in technological process, small in device investment, low in comprehensive energy consumption and excellent in natural gas product.