Chitosan has been widely used in the fields such as agriculture, chemical industry, medicine, and environmental protection due to its wide sources, natural non-toxic, rich functional groups and strong chemical activity. The research work and progress of chitosan and its derivatives in the removal of metal ions in solution are reviewed. The chemical modification methods of functional group replacement and recombination of chitosan monomer, and the physical modification method of changing the physical morphology of chitosan are introduced. The basic principles, application effects, advantages and disadvantages of crosslinking modification method, grafting modification method, magnetization modification method and molecular imprinting method are elaborated in detail. Moreover, the preparation methods and material properties of chitosan microspheres and chitosan membranes are introduced. In view of the problems in the preparation and application of chitosan and its derivatives, the research direction of combining chemical modification with physical modification to prepare new imprinted chitosan-based polymer is put forward, so as to achieve efficient and selective removal of metal ions. © 2021, Editorial Office of FINE CHEMICALS. All right reserved.