Abstract: Aiming at the problems of low efficiency and high labor intensity of 2ZY-4 type rape transplanting machine, an automatic seedling dialing out device for blanket rapeseed is designed. The single factor and multi-factor orthogonal experiments are carried out on the basic factors including the seedling angle, water content of substrate and rotational speed, to study their influence on injury seedling rate and failure rate. The results of single factor experiment showed that the device could meet the agricultural requirements when the seedling angle was 55°-65°, the rotational speed was 50-60 r/min, and the water content of substrate was 26.38%-28.56%. The results of multi-factor orthogonal experiment showed that the seedling angle had the biggest influence on the injury seedling rate, followed by the rotational speed and the water content of substrate. And the seedling angle had the biggest influence on the failure rate, followed by the water content of substrate and the rotational speed. When the seedling angle was 64.05°, the rotational speed was 52.62 r/min and the water content of substrate was 26.66%, the injury seedling rate was 5.49% and the failure rate was 11.38%. Therefore, the test shows that the device can meet the agricultural requirements and provide a practical basis for designing a kind of 4-row full-automatic transplanting machine of blanket rapeseed.