Abstract: The distilled water and 0.01 mol/L copper ion solution is respectively used to hydrate samples of geosynthetices clay liner (GCL). The 0.01 mol/L copper ion solution is replaced by the distilled water in permeability tester to measure the permeability coefficient of samples and copper ion concentrations in the leachate. The effects of different hydration treatments on GCL adsorption of copper ions and seepage performance are analyzed. The results show that different ways of pre-hydrated GCL have excellent filtering effect on copper ions. Two hydration methods for copper ion filtration capacity reach more than 99%. Compared to 0.01 mol/L copper ion solution in direct hydration, the distilled water pre-hydrated GCL has better adsorption performance, but the seepage performance deteriorated as time increases.