The present invention discloses a mercapto-modified biocompatible macromolecule derivative with a low degree of modification. The mercapto-modified biocompatible macromolecule derivative not only maintains the initial structure, physiological function and biocompatibility as much as possible, but also allows the preparation of the biocompatible macromolecule cross-linked material with a low degree of cross-linking through the effectively chemical cross-linking with the introduced mercapto group. The present invention further discloses a disulfide-bond cross-linked biocompatible macromolecule material with a very low degree of cross-linking. The disulfide-bond cross-linked biocompatible macromolecule material not only maintains the initial structure, physiological function and biocompatibility of the biocompatible macromolecule as much as possible, but also effectively prolongs turn over and reduces the solubility of the biocompatible macromolecule in vivo, better meeting the requirements of various clinical applications. The present invention further relates to the application of the disulfide-bond cross-linked biocompatible macromolecule material in the field of medicine and pharmacy.