Nanoparticles　(NPs)　have　been　widely　studied　and　applied　in　biomedicine　and　other　fields.　It　is　important　to　know　the　basic　process　of　interaction　between　NPs　and　cells　in　terms　of　cellular　endocytosis　and　exocytosis.　However,　little　attention　has　been　paid　to　the　cellular　exocytosis　of　NPs.　Herein,　using　a　multi-step　cellular　subculture　method,　we　ascertain　quantitatively　the　endocytosis　and　exocytosis　of　widely　used　TiO2　NPs　using　the　neural　stem　cells　(NSC)　as　a　cellular　model　and　ICP-AES　as　an　analytic　measure.　Irrespective　of　the　type　and　dose　of　TiO2　NPs,　approximately　30%　of　the　total　TiO2　NPs　entered　NSCs　after　48　h　incubation.　In　the　first　24　h　after　removing　TiO(2)NPs,　from　the　culture　medium,　about　35.0%,　34.6%　and　41.7%　of　NP1　(50　nm),　NP2　(30　nm)　and　NTs　(nanotubes,　100　nm　x　4-6　nm)　were　released　(exocytosed)　from　cells,　respectively.　The　release　decreased　over　time,　and　became　negligible　at　72　h.　Exocytosis　did　not　happen　during　cell　division.　In　addition,　our　results　suggested　that　both　endocytosis　and　exocytosis　of　TiO(2)NPs　were　energy-dependent　processes,　and　NPs　uptake　by　cells　was　influenced　by　serum　proteins.　Furthermore,　we　achieved　primary　dynamic　confocal　imaging　of　the　exocytosis,　allowing　tracking　of　TiO2　NPs　from　NSCs.　These　findings　may　benefit　studies　on　nanotoxicology　and　nanomedicine　of　TiO2　NPs.