Crop straw smashing and returning machine

The utility model discloses a crop straw smashing and returning machine, which comprises a frame as well as a suspension frame, a speed reduction gear box and a smashing cavity arranged on the frame; a roller is arranged in the smashing cavity; flyballs and semi-circular sawtooth blades are uniformly distributed and arranged on the roller, wherein the semi-circular sawtooth blades are symmetrically and spirally arranged from the two sides of the roller to the middle of the roller; a big belt wheel is arranged on one end shaft of the roller; the big belt wheel and a small belt wheel mounted on an output shaft of the speed reduction gear box are connected by a belt. The crop straw smashing and returning machine has simple and practical structure, runs reliably, and prevents crops fiber from twisting on the roller, thus having good smashing effect and high working efficiency.