The invention provides a semi-automatic chamfering machine. The semi-automatic chamfering machine comprises a base frame, a bottom plate, locating plates, locking pliers, a work table, micrometers, a motor, a movable sliding plate and an air cylinder, wherein the bottom plate is arranged on the base frame; a sliding rail fixing plate is installed on the bottom plate, a second sliding rail is arranged on the sliding rail fixing plate, a plurality of second sliding blocks are arranged on the second sliding rail, the movable sliding plate is connected to the second sliding rail through the second sliding blocks, a first sliding rail is arranged on the movable sliding plate, a plurality of first sliding blocks are arranged on the first sliding rail, and the air cylinder is arranged on one side of the first sliding rail; the motor is arranged on the left side of the base frame and is connected to the movable sliding plate through a pull rod; the work table is arranged on the first sliding blocks, the front side of the work table is connected to a micrometer fixing frame, and the micrometer fixing frame is provided with the micrometers; and a PLC is arranged inside the base frame. Compared with the prior art, the semi-automatic chamfering machine has the beneficial effects that propulsive assistance of the air cylinder replaces manual thrust, and the micrometers limit a jig so that accuracy control can be realized.