Sujechon is one of the most famous masterworks in korean traditional music. and it is one of the most precious products this country has ever produced. But it has been unknown that when it was composed and that whom it was composed by. It has been generally surmised that it was composed during the Shilla Dynasty. It is important to study the melodic structure of this work in various ways and to establish a model for modernization of the melodic characteristics of Korean traditional music. Firstly, the melodic structure of Dongdong that was a secular song of the Koryo Dynasty and seems to be closely related to Sujechon is dealt with, and. the analytical methods of this work such as using motivic cell and its transformations through intervalic diminutions and permutations continue to be used in the analysis of Sujechon. This paper includes a study of the melodic relationship between Sujechon and bumpae, Buddhist chants, that was imported from China during the Shilla Dynasty and also includes a study of formal structure between Sujechon and secular music of the Song Dynasty that was imported during the Koryo Dynasty.