In this work, N-benzylidene chitosan was synthesized by chitosan –benzaldehyde interaction in a homogeneous system. The modified polymers were characterized by means of infrared (IR) spectra, X-Ray diffraction and thermal analysis. Their adsorption behavior was investigated by atomic absorption spectrophotometry. The experimental results showed that N-benzylidene chitosan had better adsorption properties and higher chemical resistance than that of chitosan.