The dynamic imine bond (Schiff base bond) shows good pH responsiveness, reversibility and biological activity. Therefore, the hydrogel fabricated by the imine cross-linkages could be endowed with many new functions. Chitosan is the only alkaline polysaccharide in nature, and the abundant amino groups in the molecular chain provide the possibility of the construction of aldehyde-imine-chitosan (CSB) hydrogel. In recent years, the construction and application of CSB hydrogel have attracted wide attention, and the aldehyde cross-linking molecular structure and the design of cross-linking point have become one of research hotspots. According to the molecular structure of aldehyde crosslinker, the construction method and mechanism of CSB hydrogel, and its properties such as self-healing, drug sustained release, antibacteria, fluorescence and conductivity so on were reviewed in this paper, which could provide theoretical guidance for constructing multifunctional CSB hydrogel. It is important to design and synthetize biocompatible, multifunctional aldehyde crosslinker and improve mechanical property, self-healing ability and stimuli-responsiveness of CSB hydrogel.