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Teff is one of Ethiopia’s most important cereal crops. It is grown by about six million households on approximately 2.2 million hectares or 30% of the land area under cereal production. In Ethiopia, teff is mainly produced by smallholder farmers in a traditional way, and it is a very laborious process, both pre- and post-seeding. In order to solve the problem of Ethiopia teff mechanization seeding, a pneumatic seeding system of teff seeder was designed. The system mainly included seed-metering device, air delivery tube for seeds, distributor, fan and so on. The seed-metering device, air delivery tube for seeds, distributor was designed and analyzed, and the key parameters of pneumatic seeding system were got. The fan was selected by the key parameters, and the pneumatic seeding system experiment platform was set. The quadratic regression general rotation combination design was used for the experiment and the inlet wind speed of air delivery tube and seeding rate were taken as the influential factors. The stability variability coefficient of the full seeding quantity and the consistency variability coefficient of row seeding quantity were measured and analyzed. Through the analysis of variance and response surface analysis by Design-Expert software, the mathematical model was optimized and validated. The wind speed was 25.42m/s and seed rate was 15kg/hm2, which was optimal parameter combination. The results under the optimized experiment showed that the consistency variability coefficient of row seeding quantity was 4.96% and the stability variability coefficient of the full seeding quantity was 0.98%. The seed damaged rate was 0.12%, and seed uniformity coefficient of variation was 20.4%. The parameters can meet the standard and agronomy requirements.