When the seed flow in the pneumatic centralized drainage system enters the distributor along the side wall of the seed pipe, the mixing uniformity of the gas and the seed is low, and the consistency of the displacement of each row is poor. The spiral booster pipe was proposed, and the overall structure and working principle were expounded. The design and calculation of the seed pipe and the spiral booster pipe were carried out. Taking buckwheat as the object, the force, motion, and pressure loss analysis of the seed group in the spiral booster pipe was carried out. Based on the CFD-DEM coupling simulation method, the effects of blade number, torsion angle, spiral booster tube length, and conveying airflow velocity on the consistency coefficient of variation of each row displacement of buckwheat seeds were studied by single factor test, steepest climbing test, and central composite design test. The simulation results showed that when the number of blades was 3, the length of the spiral booster tube was 210mm, the torsion angle was 383°, and the conveying airflow velocity was 29.30m/s, the consistency coefficient of variation of each row of buckwheat was 9.83%, which was optimal. The performance verification tests of different types of booster tubes were carried out on the test bench of the pneumatic collecting and discharging system. The results showed that the variation coefficients of the consistency of each row of the buckwheat pneumatic collecting and discharging system with spiral, corrugated, and eyelet booster tubes were 5.58%, 6.85%, and 9.65%, respectively. The difference between the simulation results and the bench verification test results under the optimal parameter combination condition was 4.25 percentage points. Compared with the traditional booster tube, the spiral booster tube proposed enhanced the uniformity of gas mixing, improved the operation quality of the pneumatic collection system, and provided technical support for the design of the pneumatic collection system.