The invention discloses a straw filamentation machine. The straw filamentation machine comprises a supporting mechanism, a driving mechanism, a protection mechanism, a feeding mechanism, a shredding mechanism, a filament rubbing mechanism and a discharging mechanism, wherein the driving mechanism, the protection mechanism, the feeding mechanism, the shredding mechanism, the filament rubbing mechanism and the discharging mechanism are arranged on the supporting mechanism. A feeding hole, a straw moving channel and a discharging hole are formed in the protection mechanism; the feeding mechanismis located at the feeding hole and includes a conveyor belt and a saw disc knife roller; straw is conveyed to the shredding mechanism after being primarily crushed; the shredding mechanism and the filament rubbing mechanism are located in the straw moving channel; the shredding mechanism comprises a fixed cutter and a hob cutter, and the straw is shredded under the sliding cutting action of the fixed cutter and the hob cutter and is conveyed to the filament rubbing mechanism; the filament rubbing mechanism is used for filamentation of the shredded straw and for conveying straw filaments to thedischarging mechanism; after being screened through the discharging mechanism, the straw filaments are sent out of the machine through the discharging hole. According to the straw filamentation machine, filamentation of the straw is achieved through cooperation of feeding and division, cutting and crushing, hammering and rubbing, the filamentation efficiency is high, material accumulation is avoided, the structure is very simple, and the requirement of decentralized operation of agricultural production is met.