The invention relates to a method for preparing vanadic sulfate, belonging to the technical field of hydrometallurgy. The method comprises the following steps: a stone coal resource is adopted as a raw material; leachate with tetravalent vanadium is obtained through acid leaching; after the leachate is reduced and neutralized, vanadic sulfate enriched solution is prepared through two-stage extraction and back extraction; a vanadic sulfate product is obtained through evaporation and dehydration. The method directly prepares the vanadic sulfate by adopting technology of acid leaching-solvent extraction, has short process flow, low production cost, high vanadium yield and high product purity.