Abstract: A meshless numerical simulation method was presented to simulate the rolling of a liquid tank. In movingparticle semiimplicit method (MPS), each step of the simulation is decomposed into two steps: explicit step and implicit step. In NavierStokes equations, the relationship of partials is used to replace the difference term in old methods, and the variety of particles’ number density is used to discern free surface. As a full Lagrange method, the pass through phenomenon is always taken place in simulation.A method used in this paper can reduce the pass through phenomenon and achieve a good result.