This study is to develop an indicator system and its evaluation instrument. This report is to describe the process of developing an indicator system and evaluation instrument and explain the rationale behind this process. First, the researchers defined an ideal green school. According to the ideal green school, the author identified three sets of criteria for a green school, such as participation & partnership, reflection & learning, and ecological consideration. It also covers three operational dimensions: learning context, administration and teaching, including twenty-eight indicators in total. Each item details the EE performance and points in the direction of a good environmental education practice, with four levels of description according to the green school criteria. Tests for validity, and reliability and a norm referenced test were conducted in this research. The result shows this instrument including 28 items has high validity and high reliability (Cronbachα=0.96) with a beautiful normal curve. The indicators, evaluation instrument and norm reference table is useful for schools self evaluation to understand their performance in the environmental education and to serve as bench makers of the green school policy.