An organic positive electrode active material for aqueous redox flow batteries, and more particularly, to technology of applying an organic positive electrode active material to make up for the drawbacks of conventional aqueous redox flow batteries. An aqueous redox flow battery to which a particular positive electrode active material is applied has no problems regarding metal deposition, and can also be useful in realizing a high energy density because the positive electrode active material may be used at high concentration due to an increase in solubility in a solvent, attaining a high working voltage, and enhancing energy efficiency. Also, the aqueous redox flow battery has excellent economic feasibility because an expensive organic electrolyte is not used.