Abstract: Difference settlement is the root which causes the increase of the internal force of foundation and the substress in superstructure as well as the increase of the thickness of raft and the steel.So minimizing raft difference settlement is the most essential measure that makes the working state of buildings keep optimizational.Then in order to realize the goal,the most effective measure is to disposal and adjust the bearing stiffness of subsoils and/or pile foundations.Otherwise,how to make use of the baering capacity of soil foundation for end-bearing pile foundation is a difficult problem for the application of pile-soil interaction theory.Consequently,a kind of settlement adjustor installed at the top of piles was studied,and its constitution and work characteristics were reported.Under artificial controlling by using settlement adjustors,through self-adaptation of bearing stiffness of piles and soil,the design method of the generalized composite foundation was put forward.The design method has been proved to be successful by a practical project.