In order to improve the adaptability and working precision of the metering device on peanut seeder, the most widely used peanut seeder-Fenghua 5 is selected to study and a new declined disc metering device is designed according to the analysis of the peanut seed physical attributes. Based on the results of the orthogonal rotational combination experiment on the metering device test bed JPS-12, the performance of the metering device is analyzed and the regression equation is obtained between working parameters (metering disc velocity, declination angle, metering disc radius) and metering performance index (percentage of pass, percentage of rebroadcast, percentage of cavity and percentage of damage). Finally, it is concluded that the optimum metering performance can be obtained when the radius of the metering disc is 125 mm, the disc declination angle is 22°, and the metering disc velocity is 38 r/min. 