Abstract: Fish skin collagen has greater application potential than mammalian proteins because it is not limited by the prevalence of Creutzfeldt-Jakob disease and bovine spongiform encephalopathy. However, it is restricted by its poor mechanical properties and poor resistance to degradation. This work investigated the cross-linking mechanism, gel microstructure, mechanical properties and degradation resistance of collagen hydrogels prepared by the cross-linking of laccase (LAC) with protocatechuic aldehyde (PAL). Results showed that LAC could cross-link collagen to form a hydrogel. Meanwhile, the introduction of PAL enhanced the role of LAC in cross-linking collagen and improved the structural stability and degradation resistance of the resulting collagen hydrogels. The collagen cross-linked via LAC-PAL is an effective strategy for constructing collagen hydrogels.