Based　on　the　present　research　about　repairing　materials　for　bone　defect,　a　novel　porous　composite　scaffold　was　prepared　through　freeze-drying　technology　combining　with　in　situ　method.　The　characteristics　of　the　chitosan　and　hydroxyapatite　(HAP)　were　made　full　use.　The　porous　scaffold　had　inter-connected　pores　with　100-136　mu　m　in　diameter　and　the　porosity　was　96.1%.　The　nano　HAP　achieved　nano　dispersion　in　the　scaffold　by　the　biomimetic　method　at　room　temperature　and　improved　the　mechanical　property　of　the　scaffold.　Vitro　test　shows　that　it　is　a　bioactive　scaffold.