The invention discloses a power cable puncturing device and belongs to the technical field of electric power maintenance tools. The power cable puncturing device aims at achieving the technical effect that a detection device high in work efficiency and good in safety is provided for judging whether a power cable is electrified or not. According to the technical scheme, a base is arranged horizontally; a C-shaped vertical plate is vertically arranged on the base; an arc-shaped groove used for containing the cable is formed in the bottom end of the C-shaped vertical plate; an electroscope is arranged in the middle of the C-shaped vertical plate; a through hole which allows a cutting knife to pass through is formed in the top end of the C-shaped vertical plate; a supporting seat is vertically arranged at the top of the C-shaped vertical plate and is internally hollow; a downward-pressing mechanism for controlling the cutting knife to move downward to puncture the cable and a reset mechanism for controlling the cutting knife to reset upward after the cable is punctured are arranged at the two sides of the supporting seat correspondingly; the blade end of the cutting knife vertically passes through the supporting seat and the through hole in the top end of the C-shaped vertical plate in sequence; in addition, a vertical knife body of the cutting knife is provided with a rack; and a blade of the cutting knife is a detachable type blade. The power cable puncturing device is used for cutting and puncturing the power cable.