According to the wave conditions of Nanhui siltation engineering located in the Yangtze River estuary,this paper studies the wave characteristics of the section of hollow tetrahedron siltation embankment by physical model test.Test results show that:1) The porosity of embankment is about 66%,when the weight of each hollow tetrahedron is 3 t; 2) The reduction rate of wave energy increases linearly with the increase of embankment height,and the increasing rate of the reduction rate of wave height is averagely 4 times faster than that of wave length with the increase of embankment height;3) Compared with traditional siltation embankment which is composed of riprap and armor block,the hollow tetrahedron siltation embankment has many advantages such as significantly reducing the ground forces from the dike,simplifying construction and repair work,a strong ability to survive under strong storm action and reuse; 4) A critical stable cross-section shape of hollow tetrahedron siltation embankment under certain conditions is proposed.Under this shape condition,every 100 m of siltation embankment consists of about 3 210 blocks,the wave reduction effect of which is slightly worse than that of traditional siltation embankment at low water levels,while the effect is close to or even significantly better than that of the traditional one at high water levels.