Abstract: Bentonite is a silicate clay mineral with important applications in machinery, metallurgy, chemical industry, environmental protection, and other industries. In this paper, different low temperature plasma modified bentonite samples were obtained by changing the discharge parameters, such as the type of discharge gas, discharge time, etc. The optimal modification conditions were determined after the experiment of adsorption of methylene blue. The modified bentonite samples were characterized by FTIR, XRD, SEM, TGA, BET, etc. The results show that the specific surface area and pore volume increased, and the potential value decreased after plasma modification, while the basic structure of the modified samples did not change. The adsorption performance of bentonite sample was evaluated for methylene blue adsorption. Under certain condition of 10 mg Ar plasma-modified bentonite, 200 mL of 20 mg/L methylene blue solution, the equilibrium adsorption was as high as 183 mg/g, while the adsorption of unmodified bentonite was only 117 mg/g. Argon plasma modification can improve the adsorption performance of bentonite to methylene blue.