In order to solve the problem of small fishing boat grounding on the top of submerged breakwater, we carry out the scheme design and experimental research on the heightening of the submerged breakwater.Based on the comparison of similar projects, we propose the scheme of directly stacking and heightening the submerged breakwater with Accropode, and carry out physical wave model test to compare the three design schemes.The experiment results show that it is feasible to heighten the submerged breakwater by stacking Accropode directly.In the heightening design, the block with the same specification as the lower layer can meet the stability requirements and is convenient for construction.When the crest elevation is less than 0.2 times of the design wave above the design high water level, 1.5 times of the weight of the outer slope protection block is usually not enough , and it should be more than 2 times.