In recent years, severe scour occurs near costal structures due to frequent tsunami waves and tsunami disasters can be alleviated by vegetation. PVC tubes were chosen to simulate generalized rigid plants, and solitary waves were selected to model tsunami waves. By changing the incident wave height, the length and density of the vegetation belt and the height of the seawall, the effects of vegetation on the morphological change of a coastal zone around seawall were investigated. Empirical relations were derived to describe the relationships between the area of erosion, the area of bar as well as the balanced points of scouring and silting and the length and density of the vegetation belt, wave height, the height of water surface above the seawall, specific weight and beach slope. The results show that vegetation has a powerful impact on the evolution of beach profiles. The existence of vegetation can significantly reduce the maximum relative scouring depth inshore the seawall and the scouring location moves from the dyke toe to the vegetation belt with increasing scouring range offshore the seawall. Erosion and deposition area is affected by both the incident wave height and vegetation factors, and for the same plant model, the area of scour hole and deposit sand bar increases with higher incident wave height. The hazards of tsunami wave on seawalls can be significantly weakened with an increasing density and optimum distribution of plants.