TiO2　nanotubes　(TiO2-NTs)　are　currently　attracting　a　high　interest　because　the　intrinsic　properties　of　TiO2　provide　the　basis　for　many　outstanding　functional　features.　Herein,　we　focus　on　the　cytotoxicity　and　sublocation　of　TiO2-NTs　in　neural　stem　cells　(NSCs).　The　cytotoxicity　of　TiO2-NTs　is　investigated　using　the　methyl　tetrazolium　cytotoxicity　and　reactive　oxygen　species　assay,　the　apoptosis　assay　by　flow　cytometry.　Cell　viability　assay　shows　that　TiO2-NTs　inside　cells　are　nontoxic　at　the　low　concentration.　A　time-dependent　relationship　is　observed,　while　a　dose-dependent　relationship　is　seen　only　at　the　concentration　higher　than　150　mu　g/ml.　The　uptake　happens　shortly　after　incubation　with　cells.　TiO2-NTs　can　easily　pass　through　the　cell　membrane　and　enter　into　the　cells.　The　uptake　amount　is　increased　with　prolonging　incubation　time　and　reach　to　maximum　at　48　h.　Transmission　electron　microscopy　and　confocal　is　used　to　study　subcellular　location　of　TiO2-NTs.　It　is　found　that　TiO2-NTs　traversed　cell　membrane　and　localized　in　many　vesicles　(endosomes　and　lysosomes)　and　cytoplasm.　TiO2-NTs　in　NSCs　firstly　disperse　or　metabolism　by　lysosomal　enzymes　and　then　exocytosis　from　NSCs.