During the operation ofsuction-vibration precision seeder, the seeds on the tray were reducing continuously and suction height was declined accordingly. Through the experiments, combining with physical characteristics of rice seeds, the law of quantitative change for these seeds was obtained. A control method of suction height was proposed. Moreover, the quantity and cycle of the seeds-adding device were determined and seeding tests were conducted. The results showed that the seed-suction height control method and the seeds-adding control mode could make the seeds-layer thickness range at 8~18mm, and the absorbing rate of the seeds-suction could arrive at 94% or more, which was able to meet the requirements of precision seeding seeder.