The invention discloses a method for producing liquefied natural gas by using coke oven gas, comprising the following steps of: (1) compressing and cooling coke oven gas raw material gas; (2) dividing the cooled coke oven gas into two paths, i.e., a coke oven gas material flow A and a coke oven gas material flow B, cooling the coke oven gas material flow B, mixing the cooled coke oven gas material flow B with the coke oven gas material flow A, and then conveying the two coke oven gas material flows in a heat exchanger group to perform heat exchange; (3) conveying coke oven gas exhausted from the heat exchanger group in a gas-liquid separation tank; and (4) conveying material flows drained from the bottom of the gas-liquid separation tank in a rectifying tower, conveying material flows of the bottom of the rectifying tower in a reboiler arranged on the bottom of the rectifying tower, throttling material flows from the reboiler via a J-T valve, so as to obtain a product. The invention discloses a method adopting low-temperature rectifying by combining the current situation of the utilization of coke oven gas in China, used for separating methane from coke oven gas and producing the methane into the liquefied natural gas; and the whole process has the advantages of being simple in flow, convenient for operation, high in recovery rate of the methane, high in purity of a LNG (liquefied natural gas) product, and low in overall energy consumption.