Abstract: Abstract: A current clearing-top cutter machine for the beet leaf has presented a low cutting efficiency but high damage rate in the Chinese sugar-beet industry. In this study, a new comb-tooth cutter machine was developed for the top of beet leaf with a high pass rate of cutting top and a low breakage rate. Key parameters were determined to analyze the motion characteristics and working mechanism of the leaf and top cutter. Two kinds of special blades were used to improve the working efficiency of this machine. A parallel four-bar profiling mechanism with the comb teeth was adopted to flatly cut the top leaves of beet. As such, the profiling system enhanced the pass ability of beets and reduced the damage rate to sugar beets. The structural and performance parameters of the machine were optimized via a series of theoretical analyses according to the planting and growth characteristics of sugar beets. There was the trochoid for the motion tracking after the synthesis of any point on the tip of the knife, where the minimum speed of the knife roller was optimized to 490.3 r/min. The optimal structural parameters of the machine were also achieved, such as the clear leaf strips and leaves knife. Specifically, the leaves knife was made of a 65Mn steel plate, where the working length was 172 mm, the width was 48 mm, and the thickness was 4 mm. The oblique cutting edge of tangential cutting edge contributed to the cutting of stem seedlings, where the blade angle was 25 °. The structural parameters of clear leaf strips were obtained, where the thickness was 5 mm, the lower width was 55 mm, the upper width was 42 mm, and the length was 212 mm. A trial test was utilized to determine the parameters of the cutter top knife, ??0=6.5°, ??1=13°, ??2=6.5°. The length of the profiling rod was 320 mm, and the total profiling amount was 120 mm, indicating a standard guarantee on the specific requirements of the profiling device. The inclination angle was set to be 16.5°-19.0°. The spacing of the tooth plate was set at 40 mm, and the working width was 160 mm, according to the diameter range of the green beet head. The experimental design of the central composite was carried out to select three working parameters influencing the pass rate of cut top and damage rate of beets. A three-factor three-level orthogonal regression test was also conducted. The experimental field was set, where the moisture content of inter-loam soil was 24.2%, the hardness was 1 175 kPa, the bulk density of soil was 1.03 g/cm3, and the row spacing of sugar beet planting was 650 mm. A regression analysis was performed on the Design-expert software to determine the cutting and damage rate of beets, as well as the significance level of each factor. Consequently, a regression equation was obtained according to the contribution rate of factors. In Design-expert, the orthogonal rotation was designed to analyze the experimental data, then evaluate the significant relationship between each factor and evaluation index, and finally establish a mathematical regression model for the most optimal weight distribution according to the optimization index Y1: Y2 = 1:1. An excellent combination of parameters for the top cutter machine was a forward speed of 1.30 m/s, where the speed of the active sprocket was 732 r/min, and the torque of the torsion spring was 9.45 N·m. The best working parameters were the cutting qualification rate of 94.89 %, and the beet damage rate of 2.54 %. The proposed comb-tooth flat cutting and topping machine can provide a sound reference for the theoretical design and experimental verification in the potential topping machine of sugar beet leaves in mechanized agriculture.