The purpose of this study is to compare and analyze the contents of 20th-century music in the 17 kind of middle school textbooks which were revised in 2009 curriculum. The musical pieces of 20th-century music in the textbook was investigated according to the frequency, composer and genre and compared education contents of some musical pieces such as ‘Prelude a l``apres-midi d``un faune’, ‘Le sacre du printemps’, ‘Pierrot lunaire’ in the textbook for its learning goal. In addition, it is confirmed the elements to be learned and considered what needs to be in the text book and how to compose the contents for each musical piece by a number of references. This research can be summarized as follows. First, 20th-century music should be learned on the basis of history, society, and cultural background as well as its musical figure. It is also important to connect musical activity with other art genre such as fine art, dance, performance, etc. Second, since the learning goal of each musical piece in the textbook is different for the author``s point of view, the frame of reference should be cleared. Third, the education contents and activities of each musical piece in the text book should be composed logically and effectively depending on its learning goal. Fourth, the activities in the textbook should be consisted on the basis of student``s level and demands rather than teacher``s preference so that students can study 20th-century music during the class enthusiastically under their own initiative.