The invention discloses a cathode vibration device for electrolytic machining. The cathode vibration device comprises a cam shaft, wherein the cam shaft and a machine tool spindle rotate synchronously, a vibration shaft is arranged on the cam shaft, the end of a rotating shaft is connected with a chuck, a cam groove profile curve is arranged on the cam shaft, sliding blocks which protrude inwardsare arranged on the vibration shaft, the sliding blocks cooperate with the cam groove profile curve, so that the up-down movement of the vibration shaft is realized, and the cam shaft and the vibration shaft are provided with a photoelectric door which is consistent with the up-down movement direction of the vibration shaft. According to the cathode vibration device for electrolytic machining, twopairs of sliding block shafts and the sliding blocks are symmetrically installed, so that the stress of the vibration shaft is symmetrical; and the pulse current and vibration feeding of the cathodevibration device for electrolytic machining are synchronous, when the cathode vibration is fed to the position closest to an anode, a pulse power supply sends pulses, when the cathode vibration is away from the anode, machining gaps start to increase, the dissolution speed of the anode starts to be slowed, an electrolyte can be quickly updated, the pulse power supply does not generate the pulses,thus, stray corrosion can be reduced, energy consumption can be reduced, and the precision of electrolytic machining can be improved.