Computer graphics (CG) has enabled us to represent sand deformation by using particle-based method. On the other hand, there is a problem that sand is blown by wind, and accumulated on a road next to seashore, and it takes a lot of time and work to find where and how many sand proof fences should be installed. Therefore, this paper describes a representation method of sandy beach with a sand proof fence by CG. By considering the slope of the sand dunes, boundary conditions near sand proof fences and change of wind direction, we have succeeded to represent sandy beach that is very similar to the real one.