Abstract: The physical, chemical and biological properties of subsoil and its nutrient resource characteristics were systematically analyzed. The direct or indirect impact of subsoil on root growth was discussed. Effect of plant roots growth on the property of subsoil was explored. The methods for improving subsoil included conventional and biological amelioration. The effect of biological drilling on subsoil amelioration and its affecting factors were discussed. To utilize plant adaptation and resistance to subsoil stress and to select the stressresistance cultivar by genetic engineering were the effective approach to sustainable amelioration of subsoil. These related studies can contribute to putting the subsoil resource to rational use and exploitation,to increasing potential to agricultural production,and developing sustainable agriculture.