Nano　hydroxyapatite　(HAP)　was　employed　to　intensify　chitosan　(CS)　scaffolds　by　two　methods.　The　first　one　is　nano　HAP　crystallized　in　situ　from　the　CS　matrix　by　a　biomimetic　method　(in　situ　scaffold).　In　the　second　method　the　sol-gel　nano　HAP　powder　was　added　directly　to　the　CS　solution　(physical　mixing　scaffold).　The　distribution　status　of　nano　HAP　was　examined　by　scanning　electron　microscopy.　The　compressive　performance　was　measured　by　a　universal　material　testing　machine.　The　in　vitro　study　in　stimulated　body　fluid　was　performed　to　evaluate　the　biological　properties　of　both　scaffolds.　MTT　testing　and　alkaline　phosphatase　activity　from　human　bone　mesenchymal　stem　cell　culture　showed　differences　in　biocompatibility　and　bioactivity　between　the　scaffolds.　The　results　indicated　that　the　in　situ　scaffold　possessed　more　excellent　mechanical　and　bioactive　behaviors　than　that　of　the　physical　mixing　scaffold.　©　2011　Koninklijke　Brill　NV,　Leiden.