Abstract: In order to solve the current problem that the efficiency of mechanized seeding of Brassica chinensis is not high, and this paper designed a double-row pneumatic disc seed metering device through the combination of theoretical calculation and analysis.This paper divides the working area of the seed metering device at the beginning, and explains its working principle. Then the theoretical calculation is carried out to clarify the structure and size of the seed plate of double-row holes.In addition, the other key components of the seed metering device are theoretically analyzed to determine the arrangement of the seed cleaning device of double-row holes, as well as the structure of diversion guide device and split discharge device.Under the test conditions of rotation speed of the seed plate is 2.5 rad/s, negative pressure is 1.5 kPa, and forward speed of conveyor belt is 2.39 m/s, the bench verification test is conducted to verify the seeding performance of a double-row seed metering device. The results of bench test shows that the qualified rate, miss seeding rate, and reseeding rate of inner circle are 92.04%, 3.71%, and 4.26%, respectively; the qualified rate, miss seeding rate, and reseeding rate of outer ring are 93.70%, 3.46%, 2.84%, respectively.The coefficient of variation of the seed discharge of double-row is 8.48%, and the coefficient of variation of the total seed discharge is 4.59%, indicating that the double-row seed metering device has good seeding performance.