Sweet potato seedling recycling machine can realize sweet potato seedling recycling for feeding, avoid the waste of resources. Throwing device is an important component of sweet potato seedling recycling machine. However, throwing sweet potato seedlings has high power consumption. The dynamic analysis of sweet potato seedling in the throwing device shows that the fan blade backward tilt is more conducive to throwing than forward tilt. The power consumption analysis of the throwing device shows that when the structural parameters of the fan are fixed, the specific power consumption is high as the speed is increased. The gas-solid coupling method was applied to simulate the conveying process of the throwing device. It was found that as the speed increased, the average flow velocity in the recovery machine was gradually increased. The blade number and blade inclination had a great influence on the performance of the throwing device. Then the fan speed, blade number and blade inclination angle were taken as the experiment factors, and the specific power consumption, recovery rate and throwing speed were taken as the experiment indexes, the center combination experiment with three factors and three levels was carried out．The results showed that the influence of factors on the specific power consumption from large to small were fan speed, blade inclination, blade number; the influence of factors on the recovery from large to small were fan speed, blade number and blade inclination; the influence of factors on the throwing speed from large to small were fan speed, blade number and blade inclination; when fan speed was 880r/min, blade number was 3 and blade inclination angle was 7°, the specific power consumption of throwing device was 718m2/s2, and sweet potato seedling recovery rate was 92.79%, the throwing speed was 5.96m/s. Comparative experiments showed that after the optimization and improvement of the throwing device, the specific power consumption was reduced by 15.83%, the recovery rate of sweet potato seedlings was increased by 1.75% and the throwing speed was increased by 5.49%.