Geosynthetic clay liner (GCL) has been increasingly used as a hydraulic barrier for tailing impoundment. Under the action of different concentrations of heavy metal ions (heavy metal compounds are CuCl2 and ZnCl2), the change regulation of the free swell index, liquid limits and GCL hydraulic conductivity is researched, and the correspondences between them are analyzed. It is shown that when the concentration of heavy metal ions ranges from 0.01 mol/L to 0.1 mol/L, the free swell index and liquid limits decease with the increase of concentrations of heavy metal ions. However, further increasing of the heavy metals ions concentration ( from 0.01 mol/L to 0.5 mol/L) can’t cause the two index properties decrease continually. In the permeation test, when the concentration of heavy metal ions ranges is lower than 0.01 mol/ L, the hydraulic conductivity of GCL can remain stable. By contrast, when the concentration of heavy metal ions is up to 0.02 mol/L, the hydraulic conductivity of GCL increases with the increase of heavy metals ions concentration. Results of the study show that the index properties of a bentonite has good correspondence with the hydraulic conductivity of the corresponding GCL when the heavy metal ions concentration is higher than 0.02 mol/L and they can be used to estimate the hydraulic conductivity.