The goal of this study is to analyze the contents of environmental education reflected in the high school Integrated Science curriculum, and to suggest ways to improve environmental education-related contents in science curriculum in preparation for the new curriculum. A research team composed of professors of science education and environmental education experts jointly analyzed the 2015 revised science curriculum focused on Integrated Science subject. The results include the integrated science curriculum, which is a common subject in high school, among the 32 performance expectations of 9 units, 22 performance expectations were found to be related to environmental education factors. Looking at the environmental education area of the analysis framework, in the case of environmental knowledge, due to the nature of the science curriculum, a lot of natural environment related contents such as earth and ecological system knowledge were represented, and the environmental attitude and value area showed the lowest ratio. For environmental competency, the system & integrated thinking competency was dominant. Based on the results, ways to improve the curriculum was suggested focusing on the characteristics and goal statement of the science curriculum, the skills of the content table, and the performance expectations for each unit.