Abstract: Taking seed metering device of cotton community seeder as research object, simulation test technology was used to study seeding process of combined air suction seeder, and different boundary conditions（including pressure and airflow velocity）were set in suction port section of seeder, and velocity field and pressure field of guide groove on guide groove disc were analyzed under open conditions．Results showed that farther away from center of guide groove disc, the smaller the airflow velocity and pressure．Subsequently, boundary conditions of suction port interface of seed metering device were the same, and flow field simulation analysis was carried out for air suction hole formed after combination of air suction cup and guide groove disc．Pressure of air flow at the inlet was 300 Pa and velocity was 21.97 m/s, air field pressure of air suction hole was 2481.8 Pa, and air velocity was 61.67 m/s, which was basically consistent with results measured in the test．Finally, changes and influences of geometric parameters and dynamic parameters on airflow field of seed metering device were verified and determined, which provided theoretical support for design of trial seeder．