The biosorption behaviors and mechanisms for Ag⁺, Cu²⁺and Fe³⁺ by a novel exopolysaccharide (gellan) from Sphingomonas paucimobilis have been studied in this paper. The influences of gellan concentration, solution pH, desorption study and ionic strength on adsorption property were investigated. The gellan showed strong biosorption capability, up to 169.15 mg/g of Ag⁺, 216.09 mg/g of Cu²⁺ and 84.47 mg/g of Fe³⁺, respectively. Infrared spectrometry analysis demonstrated that the groups of O—H, C=O, C—O—C and CH₂ of the gellan which involved in metal biosorption process were the main functional groups for binding metal ions. Solvent of 0.1N Sulphuric acid showed higher desorption of Ag⁺ (94%), Cu²⁺ (90%), Fe³⁺ (86%) and adsorption-desorption process can be continued till seven cycles efficiently.