Abstract: A dynamic model of a friction pile embedded in saturated soil is established on the basis of interface model with a frequent-dependent damping between the pile and the soil. With the use of potential functions and a variable separation method, the pile dynamic response to an arbitrary vertical load is analytically derived in a closed form under the assumption of the imperfect contact between the pile and soil and an elastic bearing at the pile toe. Furthermore, a parametric study is conducted to find out the main features of the soil-pile interaction, as a result, the bearing stiffness at pile toe and soil stiffness of the pile shaft have major effects on dynamic load transfer at the contact surface of the pile and soil. And frequent dependent damping of the contact surface can restrain high frequency divergence effectively. Finally, it is shown that the theoretical curves of the present solution are in good agreement with those obtained from pile integrity test.