Abstract: To investigate the influence of pore-size effect on the dynamic responses of saturated soil foundation subjected to cyclic loading, the governing equation of nonlocal Biot theory is discretized in time- and space-domains utilizing virtual displacement principle and Newmark integrate method. The dynamic responses of saturated soil foundation subjected to cyclic loads are programed using the finite element method. The results of one-dimensional consolidation of saturated soil and dynamic responses of two-dimensional single-elastic foundation obtained by this program are compared with the published work, verifying this program. The influences of pore-size effect on the dynamic characteristics of one-dimensional saturated foundation, of two-dimensional saturated foundation and, of saturated subgrade subjected to cyclic load are investigated. The results show that: the dynamic responses of saturated soil foundation present significant hysteresis with increasing nonlocal parameter within high-frequency region, and the pore-size effect has increasing influence on the dynamic responses of saturated soil foundation with increasing frequency, which implies that the pore-size effect cannot be ignored in high frequency regions.