The invention discloses a pulverizing, shred kneading, screw compressing and compacting straw returning machine which comprises a shell, a picking and chopping device installed on the shell, a spiralconveying device installed at the position, behind the picking and chopping device, of the shell and used for conveying materials chopped by the picking and chopping device, a shred kneading and thinning device arranged on the upper side of the shell and communicated with the spiral conveying device, a screw compressing device arranged at the position, under a shred kneading box body, of the shell, communicated with the shred kneading box body and provided with a discharge pipe at the tail end, a deep loosening and deep burying device hinged to the rear side of the shell, connected with the discharge pipe of the screw compressing device and used for deeply burying the materials, a first driving mechanism for driving the picking and chopping device, the spiral conveying device and the screwcompressing device to work at the same time, and a second driving mechanism for driving a driving shred kneading roller and a driven shred kneading roller to work at the same time.