Plowing in rheological soil is a unique tillage practice in humid or water logged agricultural production regions in China. System optimization of moldboard plough for rheological soil condition is necessary for improving its performance and providing a reduced draft and minimized energy consumption. An orthogonal test using four factors with three levels was conducted to optimize plough body structural and working parameters. Significant influence of tillage depth on the plough’s performance was observed in the experiment. The optimum working condition occurred at a forwarding speed of 0.8 m/s and a tillage depth of 20 cm. This result was further evaluated and optimized with computer simulation, from which the structural parameters such as pushing angle, cutting angle, covering angle and height of plow were optimized. The simulation results proved that tilling rheological soil with a plow having a cutting angle of 35°, pushing angle of 90°and plow height of 200 mm provided the minimum specific draft of tillage, which was 0.69 N/cm2. 