Aiming at the problem of the mean overtopping of vertical breakwaters with the bed under irregular waves,the influence of the factors such as the height of the top of the breakwater,wave height,period and foundation bed on the overtopping is studied by means of physical model test.The results show that the height and period of the top of the vertical breakwater are important factors affecting the mean overtopping of the vertical breakwater.The width of the bed has a limited influence on the mean overtopping of vertical breakwaters when the relative width of bed is Bt/Hs=1~4.7.Meanwhile,the mean overtopping of vertical breakwaters with bed increases first and then decreases rapidly with the increase of the influence coefficient h*,and has a maximum value near h*=15,while it remains basically unchanged after h*=30.On the basis of the physical model experiment,the new calculation formulas on the mean overtopping of vertical breakwaters are set out,which may serve as a reference for the engineering design.