BiVO4 has extensively been studied as a promising photocatalyst and a photoanode aiming at highly efficient solar water splitting. We have successfully demonstrated the effectiveness of microwave assistance for the rapid preparation of a BiVO4 photocatalyst with high quality in an aqueous medium. The BiVO4 was highly crystalline polyhedral particles which reflect its crystal structure. Moreover, the present BiVO4 powdered photocatalyst showed higher activities for water oxidation to O-2 in the presence of a sacrificial reagent under visible light and simulated sunlight irradiation than BiVO4 prepared by the aqueous solution methods with the traditional external heating.