Abstract: Based on the problem of organic acid accumulation in bioreactor landfills with leachate recycle, a methanogenic reactor used as the pretreatment establishment before leachate recycle was introduced into the bioreactor landfill in the study. The principle of the organic refuse decomposition and gas production in the bioreactor landfill system was investigated. The results showed that the total gas production volumes for the landfill reactor, the methanogenic reactor and the bioreactor landfill system were 62.1 L, 456 L and 518.1 L, respectively, under the experimental condition. The gas generated chiefly from the methanogenic reactor where the gas production volume accounted for over 88% of the bioreactor landfill system. The gas production rate was directly proportional to organic removal rate in the methanogenic reactor, and the regression coefficient was 0.4614 L CH₄ per gram COD degraded. The kinetic model of gas production was developed based on the characteristics of organic mass decomposition in the bioreactor landfill system. The model can be used to presumedly calculate the time for the stabilization of landfilled refuse and the gas production volume in the relative bioreactor landfill system. And it also provided the theoretical basis for the utilization of landfill gas energy sources.