Taking a systematic physical model experiment under irregular wave,we analyze the factors such as the relative immersed depth of the piled baffle(t/d),relative water depth(d/Hs),relative height of the piled baffle(Δt/Hs),relative width(B/Ls)and wave steepness(Hs/Ls),which impact the wave transmission coefficient.The formula for calculating the wave transmission coefficient is achieved on the basis of the theory formula of lapa.Its calculation results are compared with experimental records,which has a great referential value for the research and design of the piled baffle permeable breakwater.