：There are wave and current penetrating phenomena in riprap breakwater,the vertical wall of breakwater with slope prism shield is subjected to the wave force in the open sea,but there is no mature calculation method for the magnitude of wave force.This paper studies the influence law of slope prism shield on the wave force of vertical wall through the physical model test of the breakwater section.The following conclusions are drawn by analyzing the experimental results.The wave force of the vertical wall with sloping prism is obviously reduced.With the increase of the top width of the slope structure,the wave force of the vertical wall decreases and the reduction coefficient decreases,However,when the width exceeds a certain value,the amplitude of the wave force reduction slows down.It is suggested that the most economical scheme should be demonstrated in combination with the model test in the design stage.The reduction coefficient of wave force in Goda formula is too large.In the preliminary scheme research stage,when the conditions for model test are not available,it is recommended to take 0.5 as the reduction coefficient of shielded vertical wall.