This paper studied the absorption of three kinds of heavy metal ions (Cu2+, Cd2+, Cr3+) on montmorillonite/humic acid complexes. The result shows that the montmorillonite absorbed humic acid can improve the absorption capacity of three heavy metal ions, and the improvement is increasingly remarkable with the rising concentration of absorbed humic acid. The Langmuir consants of adsorption isotherm can reach over 0.99. The adsorption amount of the three kinds of heavy metal ions increases with the rise of pH, but the adsorption amount decreases with ionic strength. Based on an investigation into kinetic characteristics of the three kinds of heavy metal ions on montmorillonite/humic acid complexes, the authors have found that the Elovicb equation and the two constant equation can describe the kinetic characteristics very well.