Abstract: The magnetic polymer brushes contain a magnetic core and a polymer brush shell, which is a new type of core-shell structure composing of polymer chains densely grafted to the surface of the magnetic cores at one end. The magnetic core could be either based on single magnetic nanoparticle or composite materials, where the matrix to encapsulate the magnetic nanoparticles could be inorganic materials like silica or organic materials like polystyrene or poly(methyl methacrylate). The introduction of magnetic nanoparticles enables great convenience and functionality in the preparation process and practical application of polymer brushes. Functional magnetic polymer brushes could be recycled, separated, and purified by easy operation under external magnetic field. In the last decade, with the continuous development of preparation strategies of magnetic nanospheres and surface modification techniques of nanospheres, magnetic polymer brushes have been systematically studied on structure design, functionality and applications. Magnetic polymer brushes have broad application prospects in protein adsorption and purification, bioimaging, specific detection, and catalytic enhancement, etc. This paper reviews the latest research progress in magnetic polymer brushes, and the future development direction is also anticipated.