Humans day by day have more behaviors in promoting pollution to the world by being unaware of the facts, causing impacts on all humans themselves. Creation of awareness of the environment is regarded as a guideline for helping decrease environmental pollution crises. Thus, this study of promotion of the environmental, ethical thinking system aimed to find out an efficiency of the Buddha Chinnaraj teaching approach with a requirement of 80/80, to compare ethical achievement before and after learning and to compare the environmental, ethical thinking system using the Buddha Chinnaraj teaching approach and the conventional teaching approach. The sample used in this study consisted of 80 Matthayumsueksa 5 (grade 11) students at Phutthachinnarat Phitthaya School, Amp hoe Mueang, Changwat Phitsanulok, obtained using the cluster random sampling technique. They were assigned to an experimental group of 40 students and a control group of 40 students. The instruments used for collecting data were plans for organization of learning by using the Buddha Chinnaraj teaching approach and plans for organization of learning by using the conventional teaching approach, a 40-item achievement test and a 40-item scale on ethical thinking. The statistics used for analyzing the collected data were mean, percentage, t-test (dependent samples) and F-test (ANOVA and Two-way MANOVA). The results of the study were as follows: the Buddha Chinnaraj teaching approach entitled promotion of the environmental, ethical thinking system had an efficiency of 96-25/96.87, which was higher than the established requirement of 80/80. After learning by using the Buddha Chinnaraj teaching approach Matthayomsuekas 5 students had higher knowledge, attitudes and performance in the environmental, ethical aspect than those who learned using the conventional teaching approach at the 0.01 level of significance. fter learning by using the Buddha Chinnaraj teaching approach Matthayomsueksa 5 students had higher environmental ethics than those who learned using the conventional teaching approach at the 0.01 level of significance. In conclusion, the Buddha Chinnaraj teaching approach, which has principal dharma and dharma principles in supplement as the base of the yonisomanasikara thinking system and reasons as important elements. This approach can encourage students to be alert and to generate dharma preference and originate happiness to living things around them. The students have mental freedom based on the Buddhist Teachings. Therefore, the Buddha Chinnaraj teaching approach should be supported to implement in learning and teaching in the future.