Abstract: Combining agronomic requirements such as returning corn straw to the field and meeting the needs of large-scale production, the technology of spraying composting agents and straw returning machines is integrated to design a composting agent spraying returning machine. This article provides a detailed introduction to the structure and working principle of the composting agent spraying and returning machine, and designs the composting agent spraying system; Calculations have been conducted on the transmission of the returning field system and the returning field knife rollers; Using ANSYS to solve the first six natural modes and vibration mode diagrams of the rotary tiller blade roller, and analyze the safety of the returning blade roller. Conclusion: When the machine operates at 5 km/h, the transmission ratio of the return field system is 1.3, and the output gear diameter of the side gearbox is 19 cm; The first natural frequency is much higher than the operating frequency（5.5～9.7 Hz）, so there will be no resonance, and at the maximum excitation frequency, adjacent axial blades will not interfere.