By studying the connection among the efficiency of the floating vegetation wave dissipater device, the density and region width of vegetation and gradient of the wave with sufficient flume experiments, the effectiveness of floating vegetation on wave dissipation was studied and the factors that influence the efficiency of wave dissipation, under the condition of the height of vegetation being higher than the wave height and under the effect of floating vegetation regular wave, were analyzed. The results show that floating vegetation wave dissipater device works efficiently. Under the condition of the height of vegetation being higher than the wave height, the density and the relative width of the vegetation region are the most important factors that influence the wave dissipation efficiency.