In　order　to　simplify　the　complex　process　of　preparing　TiO2　nano　bowl　array　by　traditional　method,　the　basic　principle　of　two-step　anodizing　method　was　adopted.　Namely,　during　the　first　and　second　anodizing　process,　oxidation　voltage　and　electrolyte　concentration　all　keep　as　before,　but　varying　the　anodizing　time.　The　first　anodizing　time　is　1　hour,　and　the　second　anodizing　time　changes　from　0　s　to　140　s.　After　the　first　anodizing,　as　the　initial　oxide　layer　for　the　second　anodization,　the　residual　bowl　like　pits　on　the　surface　of　Ti-sheet　may　undergo　three　stages　of　growth.　Firstly,　the　TiO2　barrier　began　to　grow　longitudinally　at　the　bottom　of　the　pit.　Then　the　dissolution　of　the　electrolyte　at　the　edge　of　the　bowl　took　effect,　and　nano　pores　appeared　in　the　bowl.　Secondly,　the　longitudinal　growth　rate　of　the　barrier　layer　and　the　dissolution　rate　of　the　electrolyte　reached　a　relative　balance.　The　bottom　center　of　the　TiO2　barrier　layer　was　first　corroded,　then　the　corrosion　position　changed　around　the　bowl　edge,　and　other　nanopores　were　corroded　laterally.　Thirdly,　the　relationship　between　the　longitudinal　corrosion　rate　and　the　transverse　corrosion　rate　was　constantly　changing,　which　showed　that　the　depth　of　the　nanopore　in　the　bowl　increased　all　the　time,　but　the　diameter　of　the　bowl　and　the　pore　first　increased　and　then　decreased.　Under　the　condition　of　the　growth　rate　of　TiO2　barrier　layer　was　in　relative　equilibrium　with　the　chemical　dissolution　rate　of　electrolyte,　and　the　longitudinal　corrosion　rate　was　relatively　consistent　with　the　transverse　corrosion　rate,　TiO2　nano　bowl　array　with　large　pore　diameter　was　synthesized.　The　optimal　second　anodizing　time　was　110　s,　and　the　diameter　of　bowl　was　133　nm.　©　All　right　reserved.