Maize straw three-dimensional returning machine

The invention relates to a maize straw three-dimensional returning machine which mainly comprises a front frame, a rear frame, a straw picking device, a straw feeding device, a straw crusher, a stubble cleaning mechanism, a straw deep placement device, a hydraulic control depth-limiting mechanism, a front motor, a rear motor, a hydraulic control system assembly and the like. The straw picking device is assembled at the front end of the front frame, the straw feeding device is assembled on the front part of the front frame, the straw crusher is assembled in the rear part of the front frame, the stubble cleaning mechanism is assembled below the front part of the rear frame, the straw deep placement device is assembled in the middle part of the rear frame, the hydraulic control depth-limiting mechanism is assembled in the rear part of the rear frame, the front motor is arranged on the front frame, the rear motor is arranged on the rear frame, and power is provided to the pre-posed motor and the post-posed motor by a hydraulic output system of a tractor. The maize straw three-dimensional returning machine during work is pulled by the tractor, and picks, crushes and deeply places the maize straws in a field as the tractor moves and meanwhile cleans stubbles, so that operations of ground mulching return to field, reclaimed soil return to field and soil deep placement return to field on the maize straws are realized.