When armor stones are dumped into water from a hopper above a water surface, a violent motion of water surface may arise from violent entries of stones. These violent behaviors bring a problem of numerical instability even in computation by particle methods. A stability of semi-implicit schemes, such as MPS or ISPH, depends on control of unphysical pressure fluctuations. Hence accurate particle methods are necessary in computation of solid-liquid two-phase flow with violent motion of water surface. In particular, around interface of solid and liquid phases, a pressure fluctuation is apt to be locally high. In this study, the DS (Dynamic Stabilization) scheme is introduced into the DEM-MPS method in order to resolve the problem, and its validity is examined by some numerical benchmark tests through the comparison with results of the previous DEM-MPS method.