Researches, both at home and abroad, on permeable breakwaters are summarized and influential factors of the permeating wave coefficient are discussed. The model of irregular waves through the vertical breakwater with culverts is simplified, and a physical model experiment is carried out to study how the relative water entry depth(t/d), the relative width of the breakwater(B/Ls), the relative water depth(d/Hs), the wave steepness(Hs/Ls), the relative height of the breast wall(Δ/ Hs) influence the wave transmission coefficients .The error causes are found by contrasting with Wiegel formula , based on which, a new fitting formula of the wave transmission coefficients are proposed according to the relative water entry depth(t/d), the relative width of the breakwater(B/Ls), the wave steepness(Hs/Ls), and its calculation results were compared with experimental records. The research results may serve as reference for the research and design of vertical breakwaters with culverts.