The utility model relates to a mouth of a river resection device, which comprises a frame, positioning mechanism and hold -down mechanism, positioning mechanism and hold -down mechanism respectively according to with the frame on, positioning mechanism includes the positioning seat, apron and cutter assembly, the positioning seat is provided with joint portion, the apron detachably install in joint portion, cutter assembly installs in the positioning seat, the apron is provided with the edge of a knife, cutter assembly includes the intraoral blade of slidable ground card income sword and installs in the cylinder of frame, the cylinder provides power ground and is connected with the blade transmission, hold -down mechanism is provided with the drive, hold -down mechanism through setting upin the positioning mechanism top with driving the slidable, the beneficial effect of the utility model embody: compress tightly the product on the apron through positioning seat and elastic press block with mutually supporting, prevent effectively that the product atress is too big and crushd by pressure and warp, combine the cylinder to promote the blade by the push pedal and carry out mouth of ariver excision, it is easy and simple to handle, simple structure, its plant use of being convenient for improves production efficiency, and with low costs, the practicality is strong.