In order to improve the working efficiency of a lawn mower and reduce its energy loss during long-term operation, the modeling and simulation analysis of the cutterhead and blade in the header is performed, and the energy-saving effect is achieved through the optimization design for the shape of the cutterhead corner area and blade. Firstly, the numerical simulation of the flow field of the cutterhead during mowing process was performed to analyze the pressure conditions of blades and the cutterhead, the speed of blades and the torque conditions of blades; Secondly, according to the law of flow field analysis, the shape of the cutterhead corner area and the blade were optimized, and three optimization schemes were proposed; Thirdly, the torque was used as the main evaluation index of the scheme energy-saving effect, the optimal design scheme was obtained by comparing with the original scheme; Finally, the optimized blade was completed and the test was carried out on a real car. The error between the test result and the simulation result was within 5%, which indicated that the simulation result was effective, and the test result verified the energy-saving effect of the optimized program. Simulation and experimental results show that the cutterhead shape has an important influence on the flow field and torque during the operation of the lawn mower. Shaped blade helps to reduce the eddy current and wind resistance of the flow field, which reduces the blade torque to achieve the purpose of energy saving and efficiency improvement.