Abstract: Mechanical behavior of pile-soil interface is an important project in the research field of pile-soil interaction.Using the digital image correlation method,the model tests of pile-soil interface mechanism characteristics were carried out in dense sand.The load transfer characteristics,the distribution regularities of shear displacement field and strain field were analyzed from the view of mesomechanics.The study results indicated that the relationship between pile shaft resistance and settlement presented softening behavior,and the settlement for ultimate shaft resistance was about three percent of pile side length.The shear sliding zone was restricted to the limited range around pile side.The maximum shear strain first appeared in pile top and pile tip,and then developed to the central part of pile.The distribution pattern of maximum shear strain along the pile shaft under ultimate load performed as big at both ends and small in the middle.These test results provided some useful references for determining reasonable pile-soil interface model and relevant numerical calculations.