The opening rate and the opening area’s position are important parameters which influence wave attenuation characteristics of perforated caisson. The wave height in front of the caisson with different opening rate was measured through physical modeling. The multipoint method was used to analyze the wave reflection coefficient, and the experiment results of the relationship between the opening rate and the wave reflection coefficient were given. Moreover, the influence of the opening area’s position on wave attenuation effectiveness was analyzed. Finally, the wave reflection coefficients of two cross sections with different width were compared.