The present disclosure relates to a bismuth vanadate electrode including vanadium-functionalized graphene quantum dots and a method for preparing the same. More particularly, it relates to a technology which is capable of, by adding graphene quantum dots (GQDs) in the process of immersing a bismuth vanadate (BiVO4) electrode in an alkaline solution to remove vanadium oxide (V2O5) excessively formed on the surface of the electrode during its preparation, protecting the electrode from the alkaline solution as the graphene quantum dots are adsorbed onto the surface of BiVO4 while V2O5 is removed, and improving the efficiency of oxygen evolution reaction (OER) when applied to a photoanode due to vanadium (V)-functionalized graphene quantum dots formed as the etched vanadium ions ((VO)43−) are adsorbed onto the graphene quantum dots.