The invention discloses a device for milling inner and outer cutting edges of diagonal cutting pliers. The device comprises a machine body and an operation table, wherein a clamp assembly used for clamping plier bodies of the diagonal cutting pliers is arranged on the operation table; the clamp assembly comprises a bottom plate, a fixed clamping block, a movable clamping block, a driving mechanismand an adjusting mechanism; the bottom plate is arranged on the operation table; the fixed clamping block is arranged on the bottom plate; a fixed clamping head is arranged on the fixed clamping block; the movable clamping block is in sliding connection with the bottom plate; a movable clamping head is arranged on the movable clamping block; the driving mechanism is arranged on the fixed clampingblock and comprises two ropes, a winding mechanism and a locking mechanism; one end of each rope is wound on the winding mechanism, and the other end of each rope is fixedly connected with the movable clamping block. Through adoption of the structure, the device is capable of effectively clamping the plier bodies of the diagonal cutting pliers and accurately positioning plier handles of the diagonal cutting pliers, so that the milling accuracy of the inner and outer cutting edges of the diagonal cutting pliers is improved.