Most of structural plane in rock mass is discontinuous but is not completely discontinuous.Experimental study find out that transmission coefficient is influenced greatly by contact area of structural plane.Propagation process of stress wave was simulated by CDEM(continuous block discrete element method).Roughness concentration of structural plane was simulated by multi-scale analysis on structural plane.The effects of contact area and distribution of structural plane on propagation of stress wave was studied.By fitting the relationship of transmission coefficients and the ratio of contact area to total area of structural plane was obtained: for longitudinal waveTp=0.258 ln(r) +1.003,for transverse waveTs=0.252 ln(r) +0.98.The study showed that transmission coefficients of stress wave and frequency spectrum of transmission wave are influenced by the distribution of contact area.