Abstract: Self-made composite adsorbent resins comprising of Bentonite/sodium lignosulfonate graft-polymerized with acrylamide and maleic anhydride (Bentonite/LS-g-AM-co-MAH) were used to investigate the effect of competitive cations and coexisting anions in supporting electrolyte on the adsorption of Pb²⁺ onto Bentonite/LS-g-AM-co-MAH. The results show that, under the presence of Li⁺, Na⁺, K⁺, Mg²⁺, Ca²⁺, Ni²⁺, Co²⁺, Zn²⁺, Cd²⁺ and Cu²⁺ in the solution, the removal capacities of Pb²⁺ reduce and the order of decreasing effect is as follows: Cu²⁺ > Cd²⁺ > Zn²⁺ > Co²⁺ > Ni²⁺ > Ca²⁺ > Mg²⁺ > K⁺ > Na⁺ > Li⁺. Under the existence of Fe³⁺ and Al³⁺ in the solution, the adsorption of Pb²⁺ decreases at pH=2.0-3.0 and increases at pH=4.0-6.0, and the effect order is Fe³⁺>Al³⁺. Coexisting anions NO₃^-, Cl^- and Br^- in the solution have negative effect on the Pb²⁺ adsorption and the decreasing order is Br^- > Cl^- > NO₃^-. SO₄^2- and PO₄^3- in the solution have positive effect on the removal of Pb²⁺ and their effects are quite similar.