Abstract: The adsorption of radionuclide 241Am by immobilized R.arrihizus from aqueous solutions and the effects of the various experimental conditions on the 241Am adsorption are studied. The results indicate that the biosorption is very efficient in the range of pH=1～7,with adsorption rate of more than 94% for 241Am. The immobilized R.arrihizus, even used repeatedly for 8 times, can adsorb more than 97% of the total 241Am in solutions. At the time, the adsorption capacity for 241Am has not reached saturation yet. The biosorption equilibrium is achieved within 2 h. No significant differences in 241Am biosorption are observed at 15～45 ℃. However,95% or 98% of the absorbed 241Am are released by EDTA solution or 2 mol/L HNO 3, respectively.