Effects of pH value and the initial concentration of Pb2+ions on the adsorption performance were investigated by using the chitosan as an adsorbent. Then, the isotherm, thermodynamics and kinetics were studied for the adsorption of Pb2+ions onto chitosan at the different temperatures. Further, the apparent activation energy was calculated. Results indicated that, the adsorption capacity of Pb2+ ions onto chitosan reach a maximum value in pH range 5~6. With increasing the initial concentration of Pb2+ions, the equilibrium capacity increase, then reach a maximum value, and finally do not change. When temperature are change in the range of 298~313 K, the equilibrium capacity increase with the equilibrium concentration of Pb2+ions and then do not change any more, and the Langmuir equation fit perfectly to the experimental datum. △G is less than zero at the different temperatures, and decrease with increasing temperature. △H is greater than zero, which indicate that the higher the temperature is, the easier the adsorption is. With increasing the adsorption time, the adsorption rate increase rapidly at the initial stage and then decrease gradually, and the adsorption kinetics follow the pseudo-second rate equation. The apparent activation energy is 18.658 kJ/mol.