Abstract: At present,with the development of industry and agriculture,heavy metal contamination of environment is intensifying,and the toxic effects on the human beings have attracted extensive attention.For the development of new adsorbent,reducing the pollution of heavy metals in water body,the chitosans were used to investigate the adsorptions of two metals of Cd2+ and Pb2+ in an aqueous solution.The absorption properties of chitosan were evaluated by the effects of pH,temperature,reaction time,adsorbent dose and initial metal ion concentration.The results showed that at pH 7-8 and pH 5-6,the chitosan had the best absorption of Cd2+ and Pb2+,respectively; low temperature was beneficial to absorption; the maximum absorption of Cd2+ was at 8 h,but of Pb2+ it always increased in the experimental period; the absorption of Cd2+ and Pb2+ was enhanced with the increase of chitosan amount; initial metal ion concentration had little effect to Cd2+,but at high metal concentration,the absorption of Pb2+ was significantly reduced.At the same time,the dynamical and the equilibrium isotherm adsorption studies of Cd2+ and Pb2+ followed the Lagergren second-order kinetic equation and the Langmuir isotherm equation in the concentration range studied,respectively.Conclusion:the adsorption capacity of chitosan is different with the changes of metal ions,in single metal solution,the adsorption capacity of chitosan for Cd2+ is stronger than Pb2+.Finally,this work systematically studies the adsorption conditions and performance of chitosan for Cd2+ and Pb2+ which may provide theory basis for chitson as heavy metals adsorbent.