Abstract: The pile generates horizontal vibration under the combined action of vertical loads and Rayleigh waves, and the vertical loads will increase the horizontal displacement due to the second-order effects. In order to study the horizontal dynamic response of piles in saturated soft soil foundation, a model for calculating the dynamic response of a single pile under the action of Rayleigh waves is established. Based on the Biot theory, the horizontal dynamic response of saturated soft soil foundation in a uniform free field is calculated. The boundary conditions are used to obtain the closure solution of soil resistance. Based on the Timoshenko beam theory, the dynamic differential equation for the pile foundation is established, and the analytical solutions of the horizontal displacement, bending moment and rotation angle of the pile are obtained. Numerical examples are used to verify the correctness of the model, and the influences of the vertical load and dimensionless frequency on the horizontal vibration of the pile are analyzed. It is found that the vertical load and pile length have a great influence on the horizontal vibration.