Well-aligned　TiO2　nanotube　arrays　were　prepared　in　aqueous　hydrofluoric　acid　electrolyte　by　anodization　in　this　paper.　The　morphology　and　composition　of　TiO2　nanotube　arrays　were　characterized　by　field　emission　scanning　electron　microscopy　and　X-ray　photoelectron　spectroscopy,　respectively,　the　field　emission　performance　of　TiO2　nanotube　arrays　was　measured　by　field　emission　testing　system,　and　the　effects　of　pH　value　of　electrolyte　on　the　morphology　(length　and　diameter)　of　TiO2　nanotube　arrays　were　investigated.　The　results　showed　that　the　field　emission　properties　of　TiO2　nanotube　arrays　were　improved　due　to　the　change　of　the　morphology　by　adjusting　the　pH　value　of　electrolyte.　When　the　pH　value　of　electrolyte　was　2.0,　the　anodized　TiO2　nanotube　arrays　had　the　lowest　turn-on　field　as　2.52　V/μm　and　a　stable　emission　current.　©　Copyright.