By the law of conservation of mass, onedimensional municipal solid waste(MSW) degradation model was proposed with considering the degradation and density fluctuation, the relationship between density, quality and volume and the degradation characteristics obtained from the degradation test.With the analysis, it was found that the settlement of degradation was positive proportional with the following three elements: the volume percentage of organic matter, the rate of degradation and the initial height.As a case study, the degradation settlement of Chongqing MSW landfill was predicted.And it was found that the relationship between the settlement and the time showed exponential attenuation trend, in which the degradation settlement of MSW landfill was large in the initial stages, and then it gradually stabilized with the time.