This study aims at analyzing and explaining the syntactic and semantic properties of the particle gwa in modern Korean. Until now, gwa is described to perform the roles such as; the function of conjunction, commutative, and comparative. Just, as the way of explanation regarding these of the functions, it`s significance that this semantic-feature was proven by treating other syntactic structure. And this semantic-feature like conjunction, commutative and comparative is not the function that can be discussed in a linear as a syntactic structure but the function that can be explained with hierarchy. In Chapter 2, according to the components that can be connected with gwa, we divided into 3 different structures such as [NP1-gwa NP2-i v], [NP1-i NP2-gwa v] and [NP1-i NP2-gwa adv v]. In Chapter 3, we have discussed the sernantic interpretation of gwa. When reviewing hierarchy of the semantic function based on the results of a study, the upper and the most basic conception is conjunction. Because this is presented the concept of relation as commutative case when connection with the preceding components irrespective of the following components like none, adverb and verb. Otherwise this is presented the concept of relation as comparative case or the particle of conjunction which is connect none, simply. Now, it should be studied in the future that how to classify the types of verb which is connected with gwa as it`s common feature and to compare the syntactic structure of gwa in diachronic with that in modern Korean.