Aiming at the problems that the existing topping device has high requirements on the shape of green head, tassel leaf state and plant spacing, and poor adaptability, etc., a tooth-plate beet topping device was studied. Through the analysis of the motion characteristics of the beet topping device, the stochastic characteristics of the motion of topping device and key influencing factors of the stress of sugar beet were clarified. Combining the working principle and movement space of the topping device, the key structure and parameters were determined to ensure the smooth top surface and low resistance. The connecting rod of the profiler was determined to be 300mm, the connecting rod was 220mm, the pitch of tooth plate was 40mm, the height of limit plate was 80mm, the lead distance was 25mm and the installation angle was 45°. According to the special position of the top cutter, the contour curve of the tooth plate was determined, and the working adaptability of the topping device was improved. With the help of Design-Expert software, a mathematical regression model of the key factors and evaluation indicators was obtained, and the influence law of forward speed and spring force on the pass rate and multi-cut rate was determined. Through parameter index optimization, the optimal parameter combination was determined: the forward speed was 1.0m/s, and the spring force was 23N. Field tests showed that tooth-plate topping device was better than the flat cutting device，the pass rate was 99.6%, and the multi-cutting rate was 0.95%, which met the requirements of the beet topping harvest index.