Abstract: The operation condition of distillation column in cryogenic liquefaction unit of low concentration coalbed methane determines the comprehensive energy consumption and overall economy of the unit. In order to effectively reduce the operating load of the distillation column and optimize the process, combined with experimental data and numerical simulation, the effects of feed gas methane concentration and reflux ratio on the design parameters and operating load of the distillation column were studied. The results show that: with the increase of the concentration of oxygen-bearing coalbed methane, the load of condenser at the top of distillation column decreases, and the load of reboiler at the bottom of the column increases. In order to improve the recovery rate of methane, the refrigerant ratio should be adjusted to increase the cooling capacity, so that the methane in the nitrogen and oxygen tail gas at the top of the column can be fully condensed; increasing the reflux ratio of the distillation column can reduce plate number and height of distillation column, but the comprehensive energy consumption needs to be improved. In practical application, the operating reflux ratio is generally 1.2 times to 2.0 times of the minimum reflux ratio.