Glycol chitosan (GC) is a hydrophilic derivative of chitosan, and has non-toxic, biocompatible, and biodegradable properties. Also, GC shows excellent solubility under a wide range of pH conditions. Therefore, it is widely studied in various biomedical fields due to the excellent solubility. The self-healing hydrogel means that the hydrogel could restore its structure and functionality after damage. This self-healing behavior can be achieved by the dynamic chemical bonds including imine bond as well as the physical bonds including hydrogen bond, and can be applicable to scaffolds for tissue engineering and drug delivery systems. In this study, the catechol-modified GC (GC-CA) conjugate was synthesized, and its self-healing hydrogel was prepared via Schiff’s base (-CH=N-) formation of GC-CA conjugate. The gelation behavior and self-healing properties of the GC-CA hydrogel were dependent on the various conditions, such as polymer concentration, degree of substitution, and pH. The results indicate that the GC-CA hydrogel will be applicable to self-healing biomaterials and tissue engineering scaffolds.