Due to the problem of low rate of garlic bulbil with upward direction after mechanical sowing in China recently, the physical and geometric parameters of Cangshan garlic were measured, and the discrete element method was used. The dynamics model of mechanism with double duck bill shape adjusting the direction of the garlic bulbil was established. The movement law of garlic in three kinds of garlic adjusting mechanism and different factors’ influences on the rate of garlic bulbil with upward direction were studied, such as the different curves of duck bill, gravity of garlics, speed of seeding and the secondary bouncing of garlics. Besides, the principle of adjusting the garlics to upward direction was also studied. The indoor planting testbed and the field prototype were manufactured. The seeding experiment was carried out, and the dynamic images of garlics’ movement at one point were recorded by visual method. It was found that the result was consistent with the simulation process, and the deviation between the rate of garlic bulbil with upward direction of the experiment and that of the simulation was less than 5%. The results showed that it was effective to use the discrete element method to analyze the movement of garlics during sowing. The rate of garlic bulbil with upward direction of the test in field can be up to 95.67%, which was increased by 4.67 percentage points.