Abstract: Abstract: Rapeseed is an important oil crop in China. High-speed precision direct-seeding technology, which has the advantages of cost saving and efficiency increasing, low lodging risk and suitable for mechanized harvest, is one of the important ways to promote the sustainable development of rapeseed industry. Aiming at the problems that the seeds of the existing pneumatic rape seed metering device are difficult to be separated quickly and sucked accurately from the seed-group during the high-speed working process, which result in leakage suction, and reducing the performance of seed metering, a sucking-seed plate combined with groove-tooth to improve the filling performance of rape high-speed direct seeding was designed in this paper, and the key structures of sucking-seed plate combined with groove-tooth were analysed and determined, the mechanical model of the seed suction for groove-tooth interference was constructed, EDEM numerical simulation was used to analyze the effects of 3 kinds of sucking-seed plates: smooth plate, groove plate and groove-tooth plate on the intensity of directional disturbance for seed-group. Combined with bench test, the optimum selection of seed sucking plate structure was carried out. The test results showed that adding of grooves and disturbing teeth on the traditional smooth plate could significantly increase the disturbance intensity of the seed-group and reduce the seed leakage suction rate. Taking the sum of average kinetic energy as the quantitative index of the seed-group disturbance intensity, the order of the sum of average kinetic energy at the same speed from large to small was: grooved tooth plate, grooved plate and smooth plate. Taking Deyouaizao as the experimental variety, suction performance tests of groove-tooth plate, groove plate and smooth plate were carried out under the work condition that negative pressure of 1.5-2.5 kPa, rotation speed in 10-150 r/min. The test results showed that leakage suction rate and the suction qualification rate of groove-tooth plate were obviously better than those of groove plate and smooth plate. There was no obvious change in the multiple suction rate of groove-tooth plate, groove plate and smooth plate. When rotation speed was greater than 90 r/min, the maximum leakage suction rate of groove-tooth plate was 7.4%, and the minimum leakage suction rate of groove plate was 14.02%, the minimum leakage suction rate of smooth plate was 30.4%, leakage suction rate was reduced by 47.2% compared with groove plate, and leakage suction rate was reduced by 75.7% compared with smooth plate. The performance test of directional disturbance suction showed that with the variety of rapeseed named Deyouaizao and Zhong Shuang 11, under the same work negative pressure, leakage suction rate was increasing, suction qualified rate was decreasing, and multiple suction rate had no obvious change with plate speed increasing. Under the same plate speed, suction qualified rate increased, and leakage suction rate decreased with the increase of negative pressure. Under the plate speed in 10-110 r/min and negative pressure in 1.5-2.5 kPa, suction qualified rate was not less than 92.0%, and the sum of leakage and re-suction rate was not more than 8.0%. Despite the variety of commonly used rapeseed seeds, the difference in sphericity and average grain size is not large, there was no suction hole blockage in the test of the high-speed precision seed metering rack of the rapeseed with groove plate, groove-tooth plate and smooth plate. Through the reasonable design of the diameter of the suction cell, the multiple suction rate and the blocking rate could be well controlled, increasing the average kinetic energy of the seed-group (the disturbance intensity) could significantly improve the filling performance, thereby improving the suction performance of the rapeseed pneumatic high-speed seed metering device and reduce the leakage suction rate. The research results showed that groove and tooth composition plate had a high suction precision and could be provide reference for structural improvement and optimization of pneumatic rapeseed high speed precision seed metering device.