In　this　work,　we　encapsulated　icariin　(ICA)　into　chitosan　(CS)/nano　hydroxyapatite　(nHAP)　composite　microspheres　to　form　organic-inorganic　hybrid　microspheres　for　drug　delivery　carrier.　The　composition　and　morphology　of　composite　microspheres　were　characterized　by　X-ray　diffraction　(XRD),　Fourier　transform　infrared　spectroscopy　(FT-IR),　scanning　electron　microscopy　(SEM)　and　differential　scanning　calorimetry-　thermogravimetric　analysis　(DSC-TGA).　Moreover,　we　further　studied　the　performance　of　swelling　properties,　degradation　properties　and　drug　release　behavior　of　the　microspheres.　ICA,　the　extract　of　traditional　Chinese　medicine-epimedium,　was　combined　to　study　drug　release　properties　of　the　microspheres.　ICA　loaded　microspheres　take　on　a　sustained　release　behavior,　which　can　be　not　only　ascribed　to　electrostatic　interaction　between　reactive　negative　hydroxyl　(OH)　of　ICA　and　positive　amine　groups　(NH2)　of　CS,　but　also　depended　on　the　homogeneous　dispersion　of　HAP　nanoparticles　inside　CS　organic　matrix.　In　addition,　the　adhesion　and　morphology　of　osteoblasts　were　detected　by　inverted　fluorescence　microscopy.　The　biocompatibility　of　CS/nHAP/ICA　microspheres　was　evaluated　by　the　MTT　cytotoxicity　assay,　Hoechst　33258　and　PI　fluorescence　staining.　These　studies　demonstrate　that　composite　microspheres　provide　a　suitable　microenvironment　for　osteoblast　attachment　and　proliferation.　It　can　be　speculated　that　the　ICA　loaded　CS-based　organic-inorganic　hybrid　microspheres　might　have　potential　applications　in　drug　delivery　systems.　©　2015　Elsevier　B.V.