The invention discloses a novel straw cutting machine used for papermaking. The straw cutting machine comprises a straw cutting machine body which comprises a feed inlet and a discharge outlet, wherein the lower end of the discharge outlet is connected with a conveying channel; the inner wall of the position of the inlet of the conveying channel is provided with a plurality of nozzles; and the position of the outlet of the conveying channel is provided with a filter screen. The novel straw cutting machine provided by the invention has novel design and reasonable structure; water is sprayed through the nozzles to flush a straw material containing impurities onto the filter screen, and impurities penetrate through the filter screen and fall into a storage pool; a piston rod periodically stretches and retracts under the action of a power device, so the filter screen periodically shakes up and down, and a clean straw material is shaken onto a conveyor belt to enter a next process, while the impurities completely fall into the storage pool in the shaking process of the filter screen; thus, strong practicability is achieved.