Based on problem that metering holes of centrifugal metering device were easily blocked and led to broken rows, the influential factors on blocking of metering hole was analyzed to develop a new structure of metering hole. The critical diameter of metering hole which only took one seed, two seeds or three seeds were determined via the model of relationship among rotation speed, structural parameters of hole and geometric properties of rapeseed. Combined with simulation of trajectory of seeds via discrete element method (DEM) software EDEM, the relevant critical diameter values of metering hole which only took one seed, two seeds or three seeds were 2.6mm, 3.5mm and 3.8mm, respectively. The test research was carried out to achieve the relationship of hole diameter, rotate speed and the performance of metering device. Experiment results showed that when the hole diameter was 3.8mm, variation coefficient of spacing row consistency and stability of full seeding quantity were less than 16.4% and 14.8%, respectively, and there was no blocked hole.