Abstract: When soil deformation between the cap and the pile toe is equal to the penetration of pile toe and the compressive deformation of pile stem, pile-soil interaction occurs. Based on this postulate, a new simplified analytical method for pile-soil interaction is proposed. According to this method, the loading which is shared by the soil between the cap and the piles can be determined at an arbitrary loading, and the quantity of piles can be conveniently determined. Meanwhile, the foundation settlement is produced by the soil deformation between the cap and the pile toe and by the compression of soil under the pile toe, and the foundation settlement can be well calculated relatively. At last, the design load of single pile can be determined by the allowed settlement of building. An example shows that the proposed method is satisfactory.