The concept of “deepwater breakwater” is discussed based on the experimental studies of stability of minor armor blocks.The primary conclusion is that a breakwater can be called deepwater breakwater while itsH/d＜0.3 and the water depth ≥20 m,and be called shallow water breakwater whileH/d≥0.3.The rationality of the regulations on the stable weights for minor armor blocks in the current code is discussed,and some suggestions are put forward to improve the regulations.Two engineering examples are given,in which weights of minor armor blocks coincide with the research results.