Oleanolic　acid　(OA)　and　ursolic　acid　(UA)　are　the　two　important　bioactive　compounds　in　Anoectochilus　roxburghii　(wall)　Lindl　(A.　roxburghii),　which　has　been　used　as　a　traditional　Chinese　medicine.　So　far,　there　has　been　no　report　to　indicate　that　A.　roxburghii　contains　these　two　bioactive　compounds.　It　is　necessary　to　develop　an　effective　method　to　extract　and　analyze　OA　and　UA　in　A.　roxburghii.　In　this　paper,　a　quantitative　method,　consisting　of　supercritical　fluid　extraction　(SFE)　followed　by　liquid　chromatography-atmospheric　pressure　chemical　ionization-ion　trap　mass　spectrometry　(LC-APCI-IT-MS)　analysis,　was　developed　for　identification　of　OA　and　UA　in　A.　roxburghii.　The　extraction　was　carried　out　by　using　CO2　as　the　supercritical　fluid　and　ethanol　as　the　modifier　before　LC　separation.　The　mobile　phase　used　for　LC　separation　consisted　of　acetic　acid　(1%,　v/v),　water　(15%,　v/v)　and　methanol　(84%,　v/v),　and　the　elution　was　performed　at　a　flow　rate　of　0.8　ml/min.　The　mass　spectrometer　was　operated　in　APCI(+)　mode　with　selected　ion　monitoring　(SIM)　to　quantify　OA　and　UA　at　m/z　439.4.　Under　optimum　conditions,　the　linear　responses　of　OA　and　UA　were　obtained　in　the　concentration　range　of　0.5-80　(r　=　0.9992)　and　0.5-50　μg/ml　(r　=　0.9989)　with　the　detection　limits　of　0.125　and　0.085　ng/ml,　respectively.　The　proposed　method　has　been　used　for　the　identification　and　quantitation　of　OA　and　UA　in　a　real　A.　roxburghii　sample.　Copyright　©　2007　John　Wiley　&　Sons,　Ltd.