Objective:　By　in　situ　polymerization　of　poly-L-lactic　acid　(PLLA)　and　nano-hydroxyapatite　(Nano-HA),　and　finding　the　best　proportion　of　composite,　so　as　to　get　ideal　interface　fixation　material.　Methods:　According　to　a　certain　ratio　(the　mass　fraction　of　Nano-HA,　respectively,　is　0%,　10%,　20%,　30%　and　40%),　composite　PLLA　and　Nano-HA　by　in　situ　polymerization,　and　test　the　performance　of　this　kind　of　new　type　of　interface　fixation　such　as,　bending　strength,compressive　strength,　elastic　modulus,　scanning　electron　microscopy　(SEM)　and　degradation　experiments　in　vitro.　Then　observe　its　mechanical　properties,　microstructure,　the　dispersion　of　Nano-HA　in　the　PLLA　and　degradation　rate　of　composite　materials.　Results:　1.　Mechanical　tests　show　that　with　the　increase　of　Nano-HA　content,　the　tensile　strength　decreases　and　the　elastic　modulus　increases;　with　Nano-HA　content　of　20%,　the　bending　strength　of　composite　materials　presents　the　peak　value　(156.8　MPa).　2.　SEM　scan　shows　the　fracture　surface　of　pure　PLLA　is　relatively　smooth;　with　Nano-HA　content　of　10%,　the　fracture　surface　shows　a　large　number　of　dimples,　and　is　obvious　rough;　with　Nano-HA　content　of　20%,　the　fracture　surface　is　uneven,　forming　a　large　number　of　dimples;　with　Nano-HA　content　of　30%　or　more,　the　fracture　surface　becomes　more　flat,　and　there　are　some　small　dimples.　3.　Degradation　experiments　in　vitro　show　the　following:　as　the　degradation　time　goes　on,　the　pH　values　of　degradation　liquid　is　gradually　reduced　and　the　mechanical　properties　of　composite　materials　also　gradually　have　some　decay.　Conclusion:　With　Nano-HA　content　of　20%,　the　interface　fixation　material　has　a　better　mechanical　properties　and　degradation　properties.　According　to　the　best　ratio,　prepare　Nano-HA/PLLA　composite　artificial　materials　with　good　performance.