Abstract: It is well recognized that the non linear behavior of pile soil interface plays an important role in analyzing the behavior of load transfer mechanism for a single pile, which can be reflected by the mobilization of shear stress developed along the pile shaft.However most previous works are focused on the linear elastic response of a single pile.In this paper, a transfer function is introduced to describe the non linear relationship between the shaft shear stress and displacement of pile shaft. Based on the proposed transfer function, an intensive research have been carried out to study the load transfer behavior for a single pile in multi layered soil.