The aim of this article is to study on prosodic structural function of phonological word in Korean. According to preceding researches on Korean, it is far from certain that the phonological word as prosodic unit has independent prosodic properties and prosodic structural meaning. In order to accomplish this purpose of this paper, it was studied by two ways. one is relation between phonological word and other prosodic units in Korean prosodic structure, the other is power of explanation power of phonological word with using two principles in prosodic structure. Two principles are Strict layer hypothesis and Prosodic licensing. The result is that the phonological word is not a prosodic unit in Korean. Because phonological word did not distinguished from accentual phrase in prosodic properties, and prosodic structure was explained clearly without phonological word layer. In addition, we found out that the prosodic boundary of phonological word can be realized right of lexical category. As a result, the phonological word in Korean does not have functions in process of prosodic structure formation, and it does not be subjugated to prosodic structure. In Korean, the phonological word is not a prosodic unit, but only phonological concept definition concerning morphological word.