Abstract: In view of the current problems of heavy labor intensity, low efficiency and high cost of manual sisal harvesting, a disc-cutting picking device of sisal hemp was designed, combined with the physical characteristics of sisal leaves and the characteristics of harvesting technology. Firstly, the structure and working principle of the whole machine were briefly described; Then, the structure of the key components of the device was designed. Through the analysis of the force and motion of the cutter in the cutting process, the structure and operating parameters such as the rotation diameter and speed of the cutter were determined; Finally, the static and modal analysis of the disc-cutter was carried out by using ANSYS, and then the cutter structure was optimized by simulation. The two factors and three-level orthogonal simulation test was carried out with the maximum stress at the bottom of the cutter and the maximum shape variable at the top of the cutter as the evaluation index and the maximum rotation radius and installation angle of the cutter as the test factors. The simulation test results show that when the cutter installation angle was 28° and the maximum rotation radius was 105 mm, the maximum deformation of the cutter was 0.09 mm and the maximum stress was 9.38 MPa, which was far less than the minimum yield strength of the cutter material 345 MPa. The minimum safety factor was 15, which was much greater than 1, and the minimum number of cycles was 10¹⁰ enters the infinite life zone. According to the first six modal analysis of the cutter, the working speed of the cutter was 800 r/min, which was far less than the limit speed. The above research shows that the stiffness, strength, safety factor and fatigue life of the cutter meet the requirements, and resonance will not occur. The research provides theoretical and technical reference for the design of sisal harvester and cutter to avoid the resonance point frequency and reduce the deformation caused by vibration.