The utility model provides a rice straw processing instrument, includes the base, the side of going up of base is distinguished for the straw cutting, the base is equipped with mobilizable manyly to the blade support, every right in the both sides in straw cutting district install the blade that to follow the vertical direction motion between the blade support, the last side -mounting of blade is on blade card slot board, the downside of blade is the cutting edge, the cutting edge and the straw cutting of blade are distinguished correspondingly, blade card slot board's the expansion end with the vertical migration device is connected to driving through the vertical migration device and reciprocating, this device has low cost, easy an implementation, and when characteristics, the feasibility is high, is worth the large tracts of land to be promoted and implements.