The important pressure formulas, which are applied to the design of composite breakwaters with the vertical wall, are as follows;
　a) the existing formulas (Hiroi's formula & the modified sainflou's formula)
　b) Ito's formula
　c) Goda' formula
　d) Nagai's formulas
　The following two works are carried out to explain the characteristics of the above-stated formulas.
　ⅰ) Calculation of the stability of existing 157 breakwaters by applying both a) the existing formulas and c) Goda's formula, and comparison of the results by the twoformulas.
　ⅱ) Design of the standard composite breakwaters by applying the above-stated formulas a)-d) under the six design conditions of water depth wave height, wave period, wave direction, bottom slope and mound height.
　The characteristics of each wave pressure formula were explained by the results of the above-stated two works.