A novel method for preparation of polymer-based magnetic microspheres was proposed by utilizing melt reactive blending, which was based on selective location of Fe3O4 nanoparticles in PA6 domains of polystyrene （PS）/polyamide 6 （PA6） immiscible blends. The morphology of PA6/Fe3O4 composite magnetic mierospheres was studied by scanning electronic microscopy （SEM）. The composite magnetic mierospheres were spherical with a diameter range of 0.5-8 μm; the diameter was sharply decreased with a very narrow distribution by adding terminal maleic anhydride fimctionalized polystyrenes （FPS） for reactive blending. Transmission electron microscopy （TEM） and thermogravimetry analysis （TGA） results showed that most of Fe3O4 was located in the PA6 microspheres. Magnetization data revealed the magnetite content of PA6/Fe3O4 microspheres was about 32 wt% and the saturation magnetization could be up to 17.2 AmE/kg.
