A knurled cylinder for pneumatic cylinder-type centralized precision metering device for rapeseed was developed.The mechanical model of the single rapeseed on the compulsive driving layer in the filling area was established via analyzing the motion trajectory of each single seed.The EDEM simulation was conducted to study the effects of the knurled structure,cylinder rotational speed and seed filling height on the dynamic characteristics of seed.The results showed that the seed filling angle and filling performance increased with the increase of the friction between the cylinder and rapeseed.The cylinder rotational speed and seeding filling height affected the angle of seed filling and towing.With the increase of the cylinder rotational speed,the normal force and tangential force between cylinder and rapeseed,the total force and velocity of the rapeseed increased linearly.With the increase of the seed filling height,the total force and velocity of rapeseed increased linearly.The dynamics characteristics of rapeseed with knurled cylinder was better than that of the normal cylinder.The results of bench experiments showed that the positive pressure was 500 Pa,the seed filling height was -5 mm,and the cylinder rotational speed was 30 r/min with good seedling performance when the negative pressure was about 2 500 Pa.When the quality index was 90.10%,the loss index was 1.56%.When the cylinder rotational speed was between 15 r/min and 50 r/min,the variation coefficient of the consistency of each line displacement,stability of the total displacement and rapeseed damage rate were less than 5.5%,2.0% and 0.2%,respectively.The results of the field experiments showed that the pneumatic cylindertype centralized precision metering device for rapeseed oil satisfied the technical requirements of rapeseed planter with which the knurled cylinder was the key part.It will provide a reference for optimizing the structure of centralized precision metering device and improving seedling performance.