Objective:　When　preliminary　tests　have　confirmed　a　nano-hydroxyapatite　(Nano-HA)　content　of　20%　of　the　polylactic　acid　(PLA)　composite　material　of　Nano-HA　interface　fixation　material　for　biomechanical　requirements,　there　is　a　need　for　further　observation　of　its　biocompatibility　and　clinical　applications,　to　provide　reference　data.　Methods:　Preparation　of　Nano-HA　content　of　20%　PLA　composite　Nano-HA　bone　substitute　material　and　extract.　The　establishment　of　the　negative　control　group　(containing　10%　fetal　bovine　serum　in　DMEM　complete　medium),　experimental　group　(extract),　the　positive　control　group　(mass　concentration　of　0.64%　phenol),　and　a　co-culture　of　rabbit　bone　marrow　mesenchymal　stem　cells　(rBMSC)　and　materials　extraction　liquid.　Observation　of　the　morphological　changes　in　rBMSC　in　culture　at　time　points　of　3,　5,　and　7　days,　the　use　of　the　MTT　assay,　and　determination　of　the　relative　growth　in　the　above　set　of　rBMSC　in　cell　culture　at　3,　5,　and　7　days,　to　judge　the　material＇s　cytotoxicity.　Results:　With　time,　the　absorbance　value　of　the　three　groups　of　cells　were　significantly　increased　(P　＜　0.01).　The　relative　growth　of　the　rBMSCs　in　experimental　group　in　the　first　3,　5,　and　7　days　was　95.3%,　96.8%　and　97.6%;　the　cytotoxicity　was　according　to　the　national　standards　I;　the　difference　was　not　significant　(P　＞　0.05)　between　the　the　experimental　group　and　the　negative　control　group;　there　was　a　significant　difference　between　the　positive　control　group　and　the　other　2　groups　(P　＜　0.05).　Cells　in　the　experimental　group　were　seen　having　normal　morphology,　and　spindle-shaped　adherent　growth.　Conclusion:　PLA　composite　artificial　bone　materials　and　Nano-HA　show　good　cell　compatibility,　and　the　values　for　cytotoxicity,　with　reference　to　GB/T16886.5.2003　(China)　standards,　are　in　the　safe　range.