Smoothed particle hydrodynamics (SPH) is a meshfree, Lagrangian particle method, which has been applied to different areas in sciences and industrial applications. In this work, SPH is used to simulate the soil-water jet interaction and erosion. In the simulation, water is modelled as a viscous fluid with weak compressibility and the soil is assumed to be an elastic-perfectly plastic material. The stress states of soil in the plastic flow regime follow the Drucker-Prager failure criterion. Both the shear and tensile criterions are used for the yield of soil particles if the yield point is reached and the total stress of the particle is scaled. Instead of computing particle pressure from an equation of state, the spherical stress is computed by dividing total stress into spherical stress and deviatoric stress. The interaction of coupling interfaces is strengthened by a penalty function to avoid unphysical penetration between particles from different materials. The obtained numerical results have shown that SPH could be a valuable method for the simulation of complex soil water interaction.