Abstract: To solve the problems of high stubble harvested by the rice machine, difficulty in straw handling, entanglement in rotary tillage components in southern double-cropping rice area, a straw return and pulping machine suitable for high stubble operations in southern paddy fields was designed and improved. Using the theory of rotary tillage and numerical analysis, the working principle of the machine was explained and the design of key components was carried out. The cutter roller and cutter mechanism were redesigned, and the combination of rotary tiller and pulverizing knives was developed. The types and parameters of the side cut, transition, and tangent parts, the combination and arrangement of the cutters were reasonably arranged, the spiral stop rod was added, and the field performance test was carried out. The test in field shows that the design can complete multiple tasks such as burying of high stubble straw in paddy field, rotary tillage and land preparation and surface leveling at one time. When the stubble height is 450 mm, its tillage depth, tillage depth stability, stubble depth, ground flatness and vegetation coverage pass rate are 168.36 mm, 89.15%, 74.50 mm, 41.64 mm and 83.20% respectively, which are in line with the design and technical requirements. Furthermore, the quality of operations can meet the subsequent agronomic requirements for rice planting. The research results can provide important technical support for the research of straw returning to the field in southern double-cropping rice area.