The invention discloses an electrolytic machining cathode of a ball nut roller path. The electrolytic machining cathode comprises a cathode head and a spring pressing plate assembly. The cathode head is provided with a nozzle. The nozzle communicates with a liquid inlet pipe. The angle between the nozzle and the axis of the cathode head is a preset acute angle. The spring pressing plate assembly comprises a sealing pressing plate and a fixing plate which are arranged oppositely. A compression spring is connected between the sealing pressing plate and the fixing plate. The cathode head is located on the side, away from the fixing plate, of the sealing pressing plate and is parallel to the sealing pressing plate. By applying the electrolytic machining cathode, precompression of the compression spring acts on the sealing pressing plate to seal a ball nut so that a closed space can be formed, working liquid is pumped in through a liquid inlet pipe under a certain liquid pressure, and the acting force of the compression spring to the pressing plate is higher than force of the liquid to the pressing plate, so that the backpressure at a machining gap outlet is formed through pressure of the working liquid, liquid flows in a convergent mode through the liquid backpressure, defects of flow lines and the like are effectively overcome, and the stability of the machining process is improved at the same time.