It is a common phenomenon that vibration or shock with drainage under dynamic load in saturated soil. However, it is complicated math-mechanical problem that calculation on kinetic response with drainage under dynamic load in saturated soil. Based on Green function of a two-phase saturated medium on 3-dimension time domain obtained by authors, the displacement Green function of solid-phase of a two-phase saturated medium on expansion source in spherical coordinate (basic solution) had been shown in this paper. The pressure Green’s function of solid-phase of a two-phase saturated medium on expansion source in spherical coordinate was obtained with physical method also. As well as the displacement and pressure Green’s functions and of fluid-phase of a two-phase saturated medium on expansion source in spherical coordinate were given by authors finally. Combining with Lamb integral formula (the representative theorem) of two-phase saturated medium, authors calculate corresponding problem of the explosive field with drainage in saturated soil. The nondimensional displacement, pore pressure and drainage flux were illustrated in figures of this paper.