Results from the experiment on sandy-loam soil with different bulk densities showed that there was a linear relation of quadratic curve between wheat yield and bulk density of soil, the highest yield occured on the soils with the bulk densities of 1.23-1.31 g/cm³. When the bulk density was larger than 1.5 g/cm³ and the penetration resistance for root was 25 kg/cm³,the root growth was hindered seriously.The experiment also proved that the soil nutrients was more in upper layer and less in lower layer, showing a T-type distribution. This is consistent with the character of the root system-growing, more in the upper and less in the lower. And therefore, keeping the original state of the soil layers and the feritility distribution is advantageous to coordination of the supply and demand of soil nutrients.