The invention belongs to the technical field of straw treatment equipment, particularly relates to a crop straw pulverizing and recycling device. The crop straw pulverizing and recycling device comprises a pulverizing bin, a material feeding hopper, electric drums, a conveying motor, a conveyor belt, material pushing rods, fixing plates, a cutting knife, a rotating shaft and a cutting motor, wherein the material feeding hopper which is arranged at the top of the pulverizing bin is used for storing straw and enabling the straw to fall into the pulverizing bin, the electric drums are driven to rotate by the conveying motor, the conveyor belt is mounted on the two electric drums, and the material pushing rods are used for pushing the straw which falls into the pulverizing bin from the material feeding hopper to the right; and the fixing plates are installed on the front wall and rear wall of the pulverizing bin, the rotating shaft is horizontally mounted on the front wall and rear wall ofthe pulverizing bin, and a material outlet is formed in the part, below the rotating shaft, of the pulverizing bin; the cutting knife which is mounted on the rotating shaft has a rectangular pyramidstructure, cutting blades are arranged on four edges, and the rectangular pyramid structure of the cutting knife is divided into at least three segments along the height of the rectangular pyramid. The device has a high working efficiency, and the cutting knife has long service life.