The invention relates to a cathode grinding head device for electrolysis grinding and milling combined machining, and belongs to the field of electrolysis machining and grinding machining. The cathode grinding head device comprises a cathode body (1) which is provided with a central blind hole (3). Abrasive particle layers (4) are arranged on the outer surface of the lower portion and the bottom face of the cathode body (1). The cathode body (1) is further provided with liquid introducing holes (2) communicated with the central blind hole (3). The radius r0 of the liquid introducing holes (2) ranges from 0.25 mm to 0.75mm, the effective electrolysis action radius r of the liquid introducing holes (2) in the size is equal to (1-1.5)*r0, and the central distance 1 of any adjacent liquid introducing holes (2) in the same layer or the same concentric circle ranges from 3r to 5r. By means of the cathode grinding head device, gap flow field distribution of electrolysis grinding and milling combined machining can be improved, and the machining efficiency and the machining quality are improved.