The purpose of this study is to present the development direction of future reading education by examining the characteristics of reading materials within the high school textbook developed as the 2015 revised curriculum. For this purpose, reading materials of high school textbooks were analyzed in Korean language, mathematics, English, integrated science, and integrated social studies. The analysis criteria of reading materials were subject type, purpose, and student activities. As a result of the study, reading materials on various themes such as humanity, liberty, culture, environment, and district were presented in the integrated society and integrated science textbook of the 2015 revised curriculum. In particular, the Korean language curriculum was composed of a unit called "reading one book in one semester" . However, most reading materials have no guidance on reading effective or reading direction, and lack of reading materials and information for extended reading. The reader's reading of the textbook was found to be simply supplementing the learning content of each unit or presenting fragmentary cues for conceptual purposes. This suggests that there is a lack of awareness of students' interest in reading, internalization of reading, and extension of reading. In this paper, we suggest supplementary materials of reading materials for expanding the high school textbooks, and explore the developmental relationship between textbooks and reading education through suggestions on aspects of textbook composition and teaching methods.