The migration of bentonite in the geosynthetic clag liner(GCL) is a universal phenomenon. The authors elaborates the negative impacts upon the performance of GCL, such as the troubles of measuring the mass of GCL per unit area and of enhancing the seepage prevention property of GCL induced by the migration of bentonite by processing a mass of tentative data of GCLs, then, analyzes the reasons causing the migration of bentonite in GCL, including the diameters of the subgrade materials, the phenomena of stress concentration, the categories of protective layer and the water content of GCL, and, finally, proposes the reasonable solution measures that should be adopted regarding the bentonite migration phenomenon caused by different reasons.The research result may be used as a reference for the manufacturing technique, building art and craft, design and study of GCL. 