For corn and soybean belt compound planting conditions under the traditional mechanical seed metering device is not easy to realize both precision seed discharge requirements, the existing pneumatic seed metering device seed discharge speed due to leakage of holes leakage charging exists leakage sowing broken stripes and other issues, a cavity plate combined hole structure of the seeding plate was designed and analyzed to determine the key structural parameters of the seeding plate, and the adsorption process and suction and transportation process mechanics model was constructed. EDEM discrete element simulation and bench test were combined to carry out the seeding plate type selection test, and the results concluded that the cavity plate combined hole seeding plate had the effect of improving the average speed of directional transport of seed populations in the seed filling chamber and increasing the dragging angle of seed filling, which effectively suppressed the leakage rate of the hole. With the installation of the preferred seed plate of the jade and soybean hybrid seed metering device as the object, with the unit forward speed and negative pressure as the test factors, with the leakage rate and the seed filling rate as the test indexes, the two-factor full factorial experimental design was done to carry out the seed filling performance test, and the results showed that when the unit forward speed was 4.0~7.0km/h, the work of the negative pressure was 3.0~4.0kPa, the leakage rate of maize and soybean seeds was less than 3.6%, and the qualified rate of seed filling was not less than 96%. Field verification test showed that under the conditions of unit forward speed of 4.0~7.0km/h and working negative pressure of 3.0~4.0kPa, the leakage rate of corn and soybean seeds sown by the seed metering device of cavity plate combination hole-type seed metering device was no more than 3.8% and 4.2%, respectively. When the working negative pressure was 3.0kPa and the forward speed of the unit was 7.0km/h, the leakage rate of sowing corn and soybeans was decreased by 14.8 and 12.6 percentage points, respectively, compared with that of the undisturbed flat seeding plate with the combination of holes in the self-disturbing cavity plate.