Abstract: To understand the interaction mechanism between tillage tools and soil in the process of strip rotary seeder, discrete element simulation software was used to simulate the typical IT225 blade, straight blade rotary blade, and chisel blade from the micro-level. It was found that the throwing soil characteristics of rotary tiller were the key factors affecting the soil backfill effect. Field tests show that the backfill rate of broken soil bodies decreases with the increase of blade shaft speed. The results show that the lateral throwing soil phenomenon of IT225 is most apparent under the high blade shaft speed, and the soil effect is the worst at the ultra-high blade shaft speed（＞280 r/min）, and the side throwing rate of soil created at super-high cutter shaft speed（510 r/min） is the highest, reaching 92%, so the backfilling effect is the worst, and the backfilling rate is only 8%, which cannot meet the requirements of seed-soil contact during sowing. In the tillage process, the chisel-type rotary blade can pick up part of the soil fragments and throw them in the forward direction of the machine. When the rotation speed of the blade shaft is 510 r/min, the soil side throwing rate is 85%, which can produce nearly 36% of the soil backfill effect. When the rotation speed is 510 r/min, the side throwing rate is only 70%, and the backfill rate is as high as 60%, which is significantly higher than the other two kinds of blades. Because of the importance of soil backfill effect on seed-soil contact, the straight blade rotary tiller has the advantages of small soil disturbance range, low side throwing rate of soil debris, good backfill effect, etc. In the cultivation process, the straight blade rotary tiller is recommended as the cultivation part over the belt rotary tiller seeder.