Abstract: Based on three-dimensional axisymmetric soil model, thevertical dynamic response of pile in radially inhomogeneous soil layers wasinvestigated with the effect of soil inhomogeneity. First, the soilsurrounding the pile was subdivided into arbitrary numerous annular zones,Second, the boundary conditions and continuum assumptions of displacementand stress between adjacent soil zones were developed. Third, the dynamicequilibrium equations of each soil zone are solved from outer to innersurrounding the pile. Third, the dynamic equilibrium equation of pile isalso solved and the analytical solutions in frequency domain andsemi-analytical solutions in time domain are obtained with the coupledcondition of pile-soil interface. The theoretical results reflect theinfluences of radial soil inhomogeneity on dynamic response of the pile andthe soil.