Monodispersed poly(styrene-co-4-vinylpyridine) [P(St-co-4VP)] microspheres were prepared by emulsifier-free emulsion polymerization. The chemical metal deposition was used to prepare magnetic P(St-co-4VP)Ni, and P(St-co-4VP)Co microspheres exhibited ferromagnetic properties. The morphology of P(St-co-4VP) and P(St-co-4VP)Ni or Co microspheres was studied by transmission electron microscopy (TEM) and X-ray diffraction (XRD). Electron spectroscopy for chemical analysis (ESCA) and XRD were used to investigate the valence changement of metals in air. The magnetic properties of the magnetic microsphere were studied. The difference of soft magnetism between P(St-co-4VP)Ni and P(St-co-4VP)Co microspheres was discussed.