Bentonite, with excellent osmotic swelling performance and low hydraulic conductivity, represents as an ideal material for the final disposal of radioactive wastes. This paper investigates bentonite and three inorganic modified bentonites (Na-Bentonite, K-Bentonite and Mg-Bentonite) in adsorption of Cs⁺, one of the major hazardous metals in radioactive waste. The effects of solution pH value, sorbent dosage and initial concentration on the adsorption performance of Cs⁺ were investigated, as well as the effects of temperature and reaction time on the adsorption capacity and removal rate of heavy metal Cs⁺. The internal structure and chemical composition of bentonite before and after adsorption were also discussed. The results indicate that the maximum adsorption rate is 95.30%, and the estimated best adsorption capacity is almost 28.2 mg/g. 1.1 g bentonite dosage and 1.0 mol/L solution concentration in alkaline environment is the most suitable conditions for cesium adsorption reaction, which can be witnessed in Na-Bentonite.