The present invention discloses an optical path/beam splitting unit and a coaxial-wire-feed cladding head thereof. The optical path/beam splitting unit includes an adjustable mirror and at least one stage of beam splitter. Several adjustable mirrors are distributed around the beam splitter. The beam splitter splits an incident laser beam into a plurality of split beams perpendicular to the incident laser beam. The split beams all are focused to a point through the adjustable mirrors. The coaxial-wire-feed cladding head includes a cladding head mirror cavity provided therein with the optical path/beam splitting unit and a wire feeding tube. The wire feeding tube is coaxially arranged with the collimated laser beam. The wire feeding tube extends out of the cladding head mirror cavity. A wire passes through the wire feeding tube and the wire feeding nozzle in order. The adjustable mirrors adjust the focusing of the split beams onto the wire.