In order to investigate the adsorbability of modified bentonite, Fourier Transform Infrared Spectrometer (FTIR Spectrometer) and Scanning Electron Microscope(SEM) were carried outto characterize the properties of samples. The amount of Cu2+, Pb2+ and Zn2+absorbed by three kinds of modified bentonite, thiol-modified bentonite, sodium-modified bentonite and acidified bentonite, in the environment of isothermal adsorption and competitive adsorption, were investigated and analyzed respectively. The results show that in the environment of isothermal adsorption, the adsorption capacity of thiol-modified bentonite is much superior to others, especially appearing adsorptive selectivity for Pb2+, the adsorption rate amounts to nearly 100%. In the environment of competitive adsorption, the adsorption rate for three kinds of modified bentonite on Cu2+, Pb2+and Zn2+ all decrease to some extent, but thiol-modified bentonite performs better in generally, which shows 10%～40% higher than the others, besides, the competitive adsorption ability of three metal ions can be given as Cu2+>Pb2+>Zn2+, which relate to their competitive ability, chemical affinity and so on. The modified process of thiol-modified bentonite is simple and the effect on adsorbing heavy metals is desirable. Therefore, it is an important study of modified bentonite and its application.