In　this　paper　tantalum　oxide　arrays　with　eximious　dielectric　films　were　fabricated　on　the　surface　of　a　pure　tantalum　sheet　by　direct　electrochemical　anodic　oxidation.　Essential　mechanism　of　preparaing　Ta2O5　by　anodic　oxidation　was　analysed.　The　parameters　of　the　anodic　oxidation　such　as　different　electrolyte,　oxidation　voltage　and　heat　treatment　influenced　on　properties　of　tantalum　oxide　were　discussed.　XRD,　EDS,　AFM　and　current　testing　instrument　with　high　resistance　techniques　have　been　used　to　characterize　the　Ta2O5　dielectric　film.　It　shows　that　crystallization　is　effectively　prevented　when　glycol　is　appened　in　the　H3PO4　electrolyte.　The　resisitant　breakdown　voltage　is　strong　as　oxidation　voltage　is　between　125　and　150V　in　which　Ta2O5　dielectric　films　are　fabricated.　The　intestine　structure　of　Ta2O5　films　is　more　compact　at　350°C/60　min　in　air　atmosphere,　by　which　the　resisitant　breakdown　voltage　of　dielectric　films　availably　enhances.