The purpose of the study was to develop cyber in-service training contents regarding environmental literacy for entry-level environmental public servants. The blended type of contents were developed, through literature review, contents analysis of other programs, and expert conferences. The validity of the contents developed was ensured experts in environment. Major research findings were as followings: First, there is a lack of time for entry-level environmental public servants to participate in the environmental in-service training programs. Therefore, cyber training can be a good solution to the problems with environmental training courses. It improves access to educational opportunities as it overcomes the limitations of time and space and provides hands-on experiences through multimedia materials that reflect the real world. Second, directions for developing cyber environmental education contents were represented in three parts; 1) strategies for developing cyber environmental education contents, 2) Models for developing cyber environmental education contents, 3) Contents selection for developing cyber environmental education contents Third, the developed contents for entry-level environmental officers consist of 4 domains: (1) the introduction to environment; (2) the natural scientific understanding of environment; (3) the humanistic understanding of environment; and (4) the social scientific understanding of environment. Fourth, the program developed was evaluated by 7 environmental education experts according to 10 evaluation items of total contents and contents development structure. In result, the validity of the program was ensured. Based on the results, some recommendations were suggested.