Abstract: Extreme climate changes have led to the proposals of higher demands on the ability of coastal protection facilities to withstand extreme waves. And the construction of an ecological coast by combining the traditional concrete-based seawalls with the coastal vegetations is a trend of coastal protection and restoration in the future. In this paper, the run-up motion of the waves on an ecological dike is studied, and the maximum run-up height of regular waves on a compound slope dike under the intervention of flexible structures is discussed based on physical flume tests. For the experiment, the materials (TPU95 and nylon) with two types of different elastic modulus are used and the salt marsh vegetations are simulated by 3D printing. The influences of the stiffness, height, density and location of the vegetations on the maximum rin-up height of the regular waves when the vegetations located in the platform area of the dike are discussed emphatically. The results indicate that the increase of the flexible vegetation zone in the platform of the compound slope dike can further reduce the maximum run-up height of the regular waves. The vegetation density is positively correlated to the attenuation rate of the wave run-up height. The maximum attenuation rate of the wave run-ip height is about 0.35 and the wave dissipation effect of the flexible TPU95 vegetation is better than that of the nylon. Moreover, the influence of the flexible vegetation height on the maximum run-up height of waves is related both to the vegetation density and to the wave period.