In order to ensure the operation efficiency of lateral deep fertilization in paddy field and improve the fertilization uniformity of lateral deep fertilization device, combined with the agronomic requirements of lateral deep fertilization of rice in cold region, a disc ejection type lateral deep fertilization device was designed, its working principle was expounded, and the key components, disc ejection type fertilizer discharger and air delivery system, were analyzed. Kinematics model of fertilizer discharging process was established, and the rotating speed of fertilizer discharge disc was an important factor affecting fertilization performance. The best work of fertilizer discharging disc was 10~60r/min by EDEM virtual simulation test. The fertilization performance experiment of lateral deep fertilization device was carried out. The results showed that the consistency of discharge amount and stability of fertilization met the national operation standard of fertilization machinery. Taking the effective working length of fertilizer tank as a factor, the average value of fertilization amount, coefficient of variation of fertilization uniformity and total fertilization amount as indicators, the single factor experiment was carried out. The results showed that when the density of fertilizer was 1.15g/cm3 and the effective working length of fertilizer tank was adjusted between 5mm and 20mm, the total fertilization amount was varied from 137kg/hm2 to 921kg/hm2, and the coefficient of variation of fertilization uniformity of lateral deep fertilization device was ranged from 5.96% to 12.77%. Compared with the straight-grooved wheel type and the inclined-grooved wheel type side-deep fertilization device, it was concluded that the disc ejection type side-deep fertilization device effectively improved the uniformity of fertilization, and there was no fertilizer crushing phenomenon in long-term operation under the premise of meeting the requirements of fertilization amount. Four special fertilizers with different densities were selected to verify the fertilizer adjustment performance of the fertilizer application device. The experimental results showed that the designed device had good adaptability to commonly used special fertilizers, and the obtained curves of effective working length of fertilizer tank and total fertilizer application with density of 0.85~1.40g/cm3 can be directly applied to field operations, which had important reference value for debugging and application of machines and tools and actual production operations.