The structure and working principle of a magnetic plate precision seed-metering device were introduced. In order to understand the seed-filling performance, the single-row permanent magnet metering elements were made as the research object and the simulation model was established by using particle discrete element method. The seed box moving speed, the magnetic suction surface magnetic field intensity, and the effect of filling position angle on seed-filling performance were simulated, and the best combination of all factors was obtained. The simulation results showed that the main factor influence filling properties was the surface magnetic field intensity of permanent magnet, and the second was the seed box moving speed. Both prototype test and simulation test showed that the metering device had good performance under these conditions of the permanent magnet magnetic field strength 150 mT,seed box moving speed 0.08 m/s, and the filling the position angle 110°. The simulation test value of the single seeding rate was 89.57%, and the actual test value was 87.93%. Simulation and test results were consistent. The results proved that it was feasible using discrete element method to analyze the performance of magnetic plate seed metering device, and the magnetic plate precision seed metering device could be used for small particles of vegetable seeds.