A　drug　delivery　system　was　prepared　for　potential　bone　regeneration.　The　fabrication　process　involved　electrostatic　self-assembly　on　sodium　alginate　to　form　global　composite　with　a　core-shell　structure.　The　core　of　microsphere　consisted　of　sodium　alginate　and　nano-Fe3O4,　which　was　prepared　by　a　microcapsule　shaping　device.　The　core　then　electrostatically　self-assembled　with　chitosan　and　finally　cross-linked　by　genipin　to　form　the　shell　structure.　Superparamagnetism　behaviors　of　nano-Fe3O　4　and　weak　ferromagnetic　behaviors　of　microsphere　were　proved　by　physical　property　measurement　system　(PPMS)　test.　The　structural　schematic　diagram　showed　the　structure　of　composite　microsphere.　The　morphology　of　the　composite　microspheres　was　evaluated　by　a　field　scanning　electron　microscope　(FSEM).　Osteoblasts　adhesion　with　microspheres　was　analyzed　by　inverted　fluorescence　microscopy.　Cytotoxicity　established　by　confocal　scanning　laser　microscope　(CLSM)　observation　confirmed　the　developed　composite　materials　with　good　biocompatibility.　Results　show　potential　applications　for　a　bone　repairing　drug　delivery　system.　©　2014　Elsevier　B.V.　All　rights　reserved.