A kind of stubble cutter was designed for cutting stubble and soil by ploughing machinery and no-tillage planter, which had the disadvantages of high resistance, high oil consumption and the impact of soil block on the cutting tool during the operation of stubble cutter. The self-regulating stubble cutter was provided with a buffer mechanism, which could adjust the cutting edge angle according to different depths of the stubble and soil characteristics to achieve low resistance and deep feed cutting. By measuring the penetration resistance of multi-point soil (soil and root soil) and the friction angle of soil and stubble, and combining with theoretical analysis and computer aided design, it was determined that the stiffness coefficient of spring of buffer mechanism of the self-regulating stubble cutter was 42N/mm. Then taking this as the main parameter and the self-regulating stubble cutter was designed. When the depth of the self-regulating stubble cutter was 25mm, the difference between the spring variable and the theoretical design value was 6.9%, and when the depth was 75mm, the difference between spring variable and theoretical design value was 7.3%. And the high speed camera showed that the performance of cutting stubble and soil of the self-regulating stubble cutter were good and the buffer mechanism was feasible, so the rationality and feasibility of the design idea were verified by both. Compared with disc cutter and notch cutter, the tillage resistance of the self-regulating stubble cutter was decreased by 13.3% and 20.6%, the oil consumption of the self-regulating stubble cutter was decreased by 19.3% and 35.3%, and the stubble breaking ratio of the self-regulating stubble cutter was increased by 16.1% and 4.6%, respectively. Therefore, the performance and work effect of the designed self-regulating stubble cutter were good.