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 salt solutions on the swelling index of bentonite, At the same time, the influence of pH and temperature on the swelling performance of bentonite was explored, and the bentonite treated with 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 salt solution inhibits the swelling performance of bentonite, and the swelling index is at least 5 mL/2g, The monovalent low-concentration NaCl solution promotes the swelling performance of bentonite, and the swelling index reaches a maximum of 56mL/2g. XRD test showed that the bentonite layer spacing after salt solution treatment decreased from 12.512 ? to 11.856 ?. SEM test analysis found that the morphology of bentonite in the high-valence salt solution changed from regular scaly to irregular flocculation. Under the conditions of a given salt solution concentration of 0.04 mol/L, a pH value of 9 and a temperature of 90°C, the expansion index increases by nearly 50%. The gel part of bentonite swells in accordance with the non-Fickian diffusion model, and the diffusion rate of water molecules is roughly the same as the relaxation rate of the gel part of bentonite.