The purpose of this study is to re-evaluate the educational significance of the Yale Seminar, which is the most influential promoter of modernization in music education. Analyzing the report of the Yale Seminar and articles about it, the following distinguishing facets were revealed: (1) the Yale's multiple recommendations made a hierarchical structure which was dominated by the nature of musicality, (2) in America, however, the Yale's significance were recognized as a factor contributing to expand repertory rather than define musicality.