The invention discloses a device and method for achieving the discharging of a DC cable, and the device comprises a supporting pedestal which contains a grounding wire for grounding and is used for bearing residual voltage indicating equipment, a high-resistance module and a metal hydraulic rod; the residual voltage indicating equipment which is located above the supporting pedestal and below thehigh-resistance module, is respectively connected with the grounding wire and the high-resistance module, and is used for judging the magnitude of the residual voltage of the DC cable according to thebrightness degree of the residual voltage indicating equipment; the high-resistance module which is connected with the metal hydraulic rod and is used for limiting the discharge speed of the DC cable; and the metal hydraulic rod which is used for making contact with a terminal outgoing line of the DC cable, so that the DC cable can discharge electricity. The device can be suitable for dischargingof the DC cable below 500kV after a withstand voltage, can be remotely controlled, is convenient to move, can conveniently see the residual voltage by utilizing the residual voltage indicating equipment, and can safely realize long-distance discharging of the DC cable.