Based on the previous research of perforated caisson, further study on wave dissipation performance of perforated caisson with permeable superstructure is carried out through physical modeling, and the reflection coefficient that changed with influencing factors, such as wave steepness, relative caisson width, relative water depth and height of superstructure from water surface and so on, is also analyzed. At the same time, empirical formula on reflection coefficient perforated caisson with permeable superstructure is obtained, which may serve as a reference for the engineering design.