Abstract: Complex of chitosan and Cu(Ⅱ)(CTS-Cu) was prepared through homogenous liquid coordination.IR,DTA,and XRD analysis were utilized to determine the structure of the complex.IR peaks of N-H,C-N,and C-O-C are red shifted.The exothermal peak of chitosan chain fragmentation decreased from 358℃ of chitosan to 285℃ of CTS-Cu.XRD peaks of chitosan located at 9.83°,10.58°,19.78°,22.45°,and 27.71° were absence in CTS-Cu's diffraction pattern.These results showed that there were coordinating bonds between chitosan and Cu(Ⅱ),and CTS-Cu contained more amorphous domains which allowed a better accessibility to reactants and thus a better reactivity.On the other hand there are some coordinating bonds within CTS-Cu that are easy to be broken.H₂O₂ was used to degrade CTS-Cu and chitosan. Under the same conditions,the degradative velocity of CTS-Cu was faster than that of chitosan,and the degraded molecular distribution of the former case was much narrower than that of the latter.After chitosan degrading for 2 h,the viscocity of CTS-Cu decreased 82.9%,while chitosan just decreased 16.6% in terms of viscosity. Dynamics of CTS-Cu degradation showed CTS-Cu could catalyze H₂O₂ decomposition.After elimination,the content of copper in low molecular weight chitosan could be less than 1.0 μmol/L.