Abstract: In order to research effect of roots system on soil mechanical pressure values and distribution and study on relationship between factors and soil mechanical pressure, the mechanical pressure of simulation roots and its influencing factors of the pressure were measured and analyzed under various diameters in different soil layer and soil bulk density respectively with homemade pressure measuring device. The result showed that the relationship between simulation roots on soil mechanical pressure and root diameter was highly significant (p<0.01) as power function, the mechanical pressure of roots on soil increased when the diameter of root increased. When the soil bulk density was the denser and the soil layer was the deeper, the mechanical pressure of roots on soil increased the more greatly. The mechanical pressure of root on soil increased when the power of wind increased. The simulation research showed that root growth could produce mechanical pressure on soil, and surface wind and other disturbance force could be passed to roots and caused the changes of this mechanical pressure. The structure and physical behavior of soil may be affected by this pressure, but the real effects need to be further test. Although simulation growth experiment was conducted with simulation roots system in this paper, it can provide guiding significance for root systems biology.