Abstract: The extracellular polymeric substances（EPS） excreted by mixed sulfate-reducing bacteria（SRB） was effective in adsorbing Zn²⁺.When the initial mass concentration of Zn²⁺ was 500 mg/L,the sorption capacity was 326.07 mg/g.The Freundlich model could well describe the experimental data,indicating zinc sorption by EPS involving chemical reaction.IR analysis demonstrated that the group of carboxyl,C—O—C of polysaccharide and lipid was involved in binding Zn²⁺,and the binding capacity of hydroxyl group and amide to Zn²⁺ was weak.