Since the complex chemical substances in the waste permeate can affect the water-absorbing swelling performance of the sodium bentonite cushion, this paper studies the influence of different valences and concentrations of chlorine salt solutions on the swelling index of bentonite. At the same time, the influence of pH value and temperature on the swelling performance of bentonite was explored, and the bentonite treated with chlorine salt solution was characterized and analyzed by X-ray diffractometer and scanning electron microscope. The test results show that the high-valence and high-concentration chlorine salt solution inhibits the swelling performance of bentonite, and the swelling index is at least 5 mL/2 g. The monovalent low-concentration NaCl solution improves the swelling performance of bentonite, and the swelling index reaches a maximum of 56 mL/2 g. XRD test shows that the bentonite layer spacing after chlorine salt solution treatment decreases from 12.512 ? to 11.856 ?. SEM test analysis find that the morphology of bentonite in the high-valence chlorine salt solution changes from regular scaly to irregular flocculation. In 0.01 mol/L NaCl solution, 0.02 mol/L NaCl solution and 0.01 mol/L CaCl₂ solution, the gel state part of the bentonite in the process of absorbing water and swelling conforms to the Fickian diffusion model, it shows that the diffusion rate of water molecules in the solution is less than the relaxation rate of the gel state of bentonite. The gel part of bentonite in the swelling process of water absorption and swelling in chloride salt solutions of other concentrations conforms to the non-Fickian swelling process, and the diffusion rate of water molecules in the solution is approximately the same as the relaxation rate of the gel part of bentonite.