Seabed seepage is one of the key factors to be considered in the design of marine engineering design，which affects the stability of structures and even causes seabed liquefaction seriously. The existing related research of the interaction between waves and seabed has not solved the problem of simulation method of seabed in the laboratory yet. Based on this，we study the similarity rate of permeable sandy seabed model under wave action. Based on the condition that the prototype pore water pressure is similar to the model value，we propose a similarity criterion for simulating seabed in laboratory through a series of wave flume physical model tests. The results show that the relationship between the similarity scale of sandy seabed and model geometric scale is λseabed=λ1/3.