Lignin is the most abundant aromatic compound found in nature. The rich functional groups of lignin are responsible for its antibacterial, antioxidant, anti-ultraviolet, and biocompatible properties. As modified lignin has a higher molecular weight, water solubility, and better surface activity, it is a good candidate for the construction of new biological materials. Lignin-based hydrogels are a type of functional materials with broad application prospects in the biomedical field. This review aimed to introduce the biological properties of lignin and the application of lignin-based hydrogels in the biological field.