Abstract: In soilless culture, the balance between aeration and moisture is a key factor to affect the growth of plant, while the balance point is fallen under the influence of bed structure, substrata and waterlogged-layer in primary consideration. This paper paid more attention on the effect of the bed structure on the aeration. From the computer results of the equation of air movement in substrata, it is found that the bed on stilts is better in aeration. Combined with waterlogged layer, its performance will be further improved.