Abstract: In order to explore effect of different suppression intensity on growth characteristics of oat, a suppression test device with adjustable suppression intensity was designed．Interaction between suppression wheel and soil was analyzed．Through force analysis and formula derivation, relationship between suppression strength and counterweight was obtained．Through field calibration test, test counterweight under different suppression intensity was calculated．Agronomic characteristics of oat such as emergence rate, dry matter accumulation of roots, stems and leaves at seedling stage and yield were tracked and analyzed by field experiment．Results showed that when suppression intensity was 45 kPa, growth and development of oats were the best, emergence rate, dry matter accumulation of roots at seedling stage, dry matter accumulation of stems and leaves, and yield of oats were 78.33%, 0.088 g/plant, 0.546 g/plant, 2 501.25 kg/hm², which increased by 30.09%, 33.33%, 32.52%, and 16.58% compared with that without compression, respectively．