clay liner (GCL) and attenuation liner (AL) was developed to investigate the transport of organic pollutants in the composite liners. Degradation of the organic pollutants in AL is considered. The analytical solution to the model was obtained, and the results are in good agreement with those from Pollute v7 software, showing the reasonability of the proposed model. The effect of biodegradation on diffusion of organic pollutants was investigated on the basis of the proposed model. The equivalence between GCL+AL and the compacted clay liner (CCL) is discussed with consideration of biodegradation. The results show that the bottom flux of the GCL+AL composite liners is reduced when the degradation half-life of organic pollutants in AL decreases. The standard 0.75 m CCL can be replaced by a combination of a GCL and an AL with a thickness of more than one meter under the calculation conditions described in this paper.