The invention discloses a preparation method of high-purity 
vanadium pentoxide. The preparation method comprises the following steps of: returning and dissolving coarse 
vanadium in aqueous alkali, and filtering the solution to remove 
metal impurities, which are subjected to 
precipitation reaction with the aqueous alkali, in the coarse 
vanadium, thus obtaining a primary returned solution; slowly pouring the primary returned solution into a 
sulfuric acid solution, adjusting the pH value of the solution to be 1.0-2.0 to obtain a liquid-
solid mixture, and performing 
solid-liquid separation on the liquid-
solid mixture; filtering and washing precipitates obtained from the solid-liquid separation of the mixture, and returning and dissolving the mixture into the aqueous alkali, thus obtaining a secondary returned solution; adding 
ammonium sulfate into the secondary returned solution for precipitating vanadium, and filtering the solution to obtain 
ammonium metavanadate; and 
processing the 
ammonium metavanadate to obtain the high-purity vanadium 
pentoxide. The preparation method adopting 
multiple stages of returned dissolving can be used for effectively removing the 
metal canon impurities of the vanadium 
pentoxide, and further obtaining the high-purity vanadium pentoxide with the 
metal canon 
impurity contents of less than 0.001% and the vanadium pentoxide content of 99.99%.