The invention generates the water grids in each of the visible range of the water wave maps and the third dimension coordinates according to the intersecting points. The third dimension coordinates are corresponded to the actual water height. Finally, the invention generates a water surface having the wave change according to the third dimension coordinates. And the invention can obtain the information of the water height dynamically, generate the water surface image having the light change, including the effect of reflection and refraction, according to the information of the water height, and make the water image corresponding to the actual water.