The invention relates to study tools, in particular to an ink injecting writing brush. A writing brush rod is of a hollow structure, the lower portion of the writing brush rod is connected with a hollow connecting part, the lower end face of the connecting part is provided with a through hole, the diameter of the through hole is 3 mm, the lower portion of the connecting part is connected with a writing brush point, the writing brush point wraps the connecting part, and the position, in the connecting part, of the lower end of the writing brush rod is filled with electrolytic condenser paper. The writing brush is simple in structure.