It　has　been　well　accredited　that　the　neural　stem　cells　(NSCs)　derived　from　bone　marrow　stroma　cells　(BMSCs)　can　be　used　as　the　therapeutic　application.　However,　their　efficacy　and　safety　in　therapeutic　application　are　uncertain.　In　this　experiment,　the　trace　marking　and　oncogenicity　of　NSCs　derived　from　BMSCs　(BMSCs-D-NSCs)　were　studied.　The　BMSCs　were　harvested　by　gradient　centrifugation　and　cultured　in　＂NSCs　medium＂　in　vitro.　The　verified　CD133/Nestin-positive　BMSCs-D-NSCs　were　then　transplanted　into　nude　mice　to　detect　the　oncogenicity,　into　the　right　lateral　cerebral　ventricle　or　right　caudae　putamen　and　substantia　nigra　to　examine,　whether　the　symptoms　were　improved　in　Parkinson＇s　Disease　(PD)　models　after　transplantation,　by　both　SPECT　image　assay　of　dopamine　transporter　(DAT)　in　corpus　striatum　and　its　average　standard　uptake　value　(SUVave)　in　corpus　striatum　and　thalamus.　Tissue　samples　and　surviving　model　animals　were　studied　at　1,　3,　and　6　months　post-transplantation.　Before　transplantation,　the　cells　were　labeled　with　BrdU　or　rAAV-GFP　for　the　pathological　sections,　and　with　Feridex　for　the　in　vivo　trace　by　MRI　assay.　The　concanavalin　A　(ConA)　agglutination　test,　stop-dependence　test　with　soft　agar,　karyotype　analysis　of　chromosome　G　zone　in　BMSCs-D-NSCs,　and　the　nude　mouse　neoplasia　test　were　also　performed.　The　BrdU,　rAAV-GFP　or　Feridex　can　be　used　as　trace　markers　of　BMSCs-D-NSCs　during　transplantation.　The　transplanted　BMSCs-D-NSCs　displayed　neither　toxicity　nor　neoplasia　up　to　6　months　in　vivo,　but　could　play　an　important　role　in　improving　the　symptoms　of　the　animals　with　degenerative　diseases　like　PD.