Abstract: Based on the unstructured-grid approach,this paper presents a numericalwave flume mode,l in which the Navier-Stokes equation is discretized using the three step finite element method(FEM) and the free flow surface can be captured by the Computational Lagrangian Eulerian. A dvection Remap and the Volume of the Fluid(CLEAR VOF) method.This CLEAR VOF FEM model is used to smiulate the mipinging process by broken wave on the vertical break water built on a mild slope.The result shows that the simulated breaking wave force and flow field are in good agreement with the particle miage velocimetry PIV data,which indicates the applicability of the CLEAR VOF FEM model.