The purpose of this study is to analyze the aspects of inquiry tendency, scientific attitude, inquiry method, utilization of biological history, and connection of real life in high school biology textbooks of South and North Korea. The exploration tendency of biological textbooks was analyzed according to Romey's analysis of textbook texts, visuals, questions, discussions, and experimental activities. Other characteristics were analyzed qualitatively based on the texts presented. The research results are as follows. South Korea's life science 1 textbooks and North Korea's higherlevel middle school 1 biology textbook showed almost similar inquiry trends, but South Korea's life science 1 textbooks showed a higher inquiry-oriented tendency in terms of sentences, visuals, and questions. However, compared to the textbooks in South Korea, North Korea's higher-level middle school 1 biology textbook specifically suggested the nature of life sciences, the relationship between knowledge, and the application of life. Also, life science 1 textbooks in South Korea tend not to distinguish between inductive and hypothetical deductive inquiry, whereas higher-level middle school 1 biology in North Korea provide some examples of inductive and hypothetical deductive inquiry and present them separately for each unit. The degree of use of biologists has provided many cases in which the biological textbooks of North Korea are much more diverse and richer than the life science textbooks of South Korea. In addition, the degree of linkage with real life tended to give examples more frequently in North Korean biological textbook than in South Korean life science textbooks. In reference to this study, it is necessary to reinforce what is related to the nature of science in the development of life science 1 textbooks in South Korea.