The invention discloses a method of extracting vanadium pentoxide from stone coal vanadium ore acid-mixed pile ore. The method comprises the following steps: crushing and coarsely crushing the vanadium-containing stone coal vanadium ore till the granularity is less than 5mm; adding acid and water into the crushed ore and uniformly mixing and piling; leaching piled ores by clean water in normal temperature; filtering pulp to generate a leaching liquid and leaching residues; pulpifying and washing the leaching residues as a building material for producing cement or bricks; extracting the leaching liquid which is neutralized by lime and sodium carbonate by an extractant; reversely extracting by sulfuric acid; and oxidizing the strip liquor by hydrogen peroxide, neutralizing by ammonium water and depositing vanadium in acidity to generate red vanadium and then calcining to generate vanadium pentoxide. The vanadium leaching efficiency is greatly improved to over 90%, and the total recovery rate reaches up to over 85%.