One dimensional chloridion movement in a Kaolin clay liner is modeled by using 400 g-t centrifuge machine. Liner model is prepared by consolidating a high water content Kaolin slurry in 1 g condition. The breakthrough of chloridion in the Kaolin clay liner under high hydraulic head is successfully simulated at 50 g centrifugal acceleration for 3 hours and 52 minutes. The results indicate the liner model experienced further consolidation in the centrifuge due to the induced seepage force, and the consolidation-induced seepage resulted in a transient flow in the early stage. The transient flow influenced the chloridion movement process, which is inconsistent with the condition of Ogata’s analytical solution (1961) for one-dimensional advection-dispersion problem. An equivalent time method is proposed in this paper to analyze the test results. The prototype breakthrough time was predicted by the fitted parameters. The experimental results demonstrated that under a hydraulic head of 10 m, the breakthrough time for 2 m thick Kaolin clay liner with a hydraulic conductivity of 3.2×10^-9m/s was 1.97year, and the stable leakage rate was 0.604 m/yr.