To improve the wave-dissipation and water permeability of the horizontal plate breakwater，we design a horizontal plate breakwater with semi-perforated on wave-facing side.Under different conditions of relative plate width，submerged depths，and wave heights，we use physical modeling tests to study the transmission coefficient Kt，reflection coefficient Kr，and energy dissipation coefficient Kh of the two types of horizontal plate breakwaters including the non-perforated type and the semi-perforated on the wave-facing side type，and systematically compare the wave-dissipation performances of the two types of horizontal plate breakwaters.The results show that under test parameters，the transmission coefficient of the semi-perforated horizontal breakwater on the wave-facing side is smaller than that of the non-perforated horizontal breakwater，and the transmission coefficients of the two types of horizontal plate breakwaters both reach the minimum value when the conditions of relative plate widths are 0.166 or 0.212.While the trend of the reflection coefficients of the two types of horizontal breakwaters is similar，and the reflection coefficients of the semi-perforated horizontal breakwater on the wave-facing side are small.The overall reflection coefficients of the two types of horizontal plate breakwaters are similar in trend，and the overall reflection coefficients of the semi-perforated horizontal plate breakwaters on the wave-facing side are small；the overall energy dissipation coefficients of the semi-perforated horizontal plate breakwaters on the wave-facing side are larger than that of the non-perforated horizontal plate breakwaters，and they reach the maximum values when the relative widths are 0.166 or 0.212.The wave dissipation performance of the horizontal plate breakwater with semi-perforated on the wave-facing side is better than that of the non-perforated breakwater.