Abstract: Based on the in situ test of pile soil interaction of filling pile, combining with the properties of soils in Xian, and modelings pile soil interaction of concrete filling pile in the loess area by using finite element method, the authors studied pile soil interaction, regularity of load transferring, and the relation between relative displacement and lateral friction resistance of the pile. By comparing of pile load test data,it is found that the modeling result by three dimensional finite element method is similar to that of actual measurement. Moreover, the essence of pile soil interaction is revealed. It provides a basis for the selection of optimum pile length and the definition of pile bearing capacity.