To improve the use efficiency of seeder，a pneumatic precision metering device for rapeseed and wheat was designed in view of the adjacency of sowing time of rape and wheat in Yangtze river valley，and a new kind of structure of wheat seeding plate with seed guiding strips inlaid was presented. The working principle，main structure and performance parameters of the pneumatic metering seeder were analyzed and determined; experimental study on the relationships between main performance indices and rotating speed of seeding plate，negative pressure in sucking chamber and positive pressure in releasing chamber were carried out. The test indicated that the device works well with both rapeseed and wheat seed; the wheat seeding plate inlaid with guiding strips enhances wheat quality index by 27.31% and reduces missing index by 25.86%; for precision sowing rapeseed，when the rotating speed of seeding plate is 18r/min，negative pressure， positive pressure，the quality index and the missing index 〖JP3〗are -2200Pa, 400Pa, 90.02% and 2.59%, respectively; for precision sowing wheat seed, when the rotating speed of seeding plate is 15r/min，negative pressure，the quality index of single row and the missing index are -2300Pa, 90.62% and 2.96%, respectively. And the test in field indicated that the device is provided with highmetering accurateness and meets agronomic requirement of planting rapeseed and wheat.