3.0%。In order to define the optimum performance parameters of pneumatic precision metering device for rapeseed, single factor and orthogonal experiments were carried out, with the experimental factors of rotational speed of metering disc, speed of seed belt, pressure and vacuity, employing eligible index, multiple index, miss index, seed damage rate as judging indexes. Single factor experiment showed that the damage rate of seed is zero in every group of experiments，and the other three indexes were remarkably influenced by rotational speed of metering disc, pressure and vacuity. Furthermore，orthogonal experiment indicates that when the pressure is 440Pa, the vacuity is -834Pa and the rotational speed of metering disc is 15r/min, the eligible index reaches as high as 94.2%, both of the multiple index and the miss index are lower than 3.0%.