Abstract: Now a days learning activities for environmental education or environmental studies mainly focus on the integration of people’s ways of life into the learning activities by examining the social contexts and environment around the learners so that the learners would have direct experience from nature enabling them to learn meaningfully. Besides, at present, the ideas of sufficiency economy philosophy have also been integrated into learning and teaching activities of environmental studies aiming to inculcate the learners to follow the essence of the philosophy which consists of three pillars: moderation, reasonableness and self-immunity and two conditions: knowledge and integrity. The purposes of this research were three fold: to develop the learning activity entitled Life and Environment following the sufficiency economy philosophy for Prathomsuksa 6 students, to compare the learning achievements of the students before and after using the learning activity and to compare the students attitudes towards environmental conservation before and after using the activity. The samples were 30 Prathomsuksa, 6 students studying in the second semester of the 2008 academic year at Sapradoo School, Wichianburi District, Petchaboon Province. The experiment was carried out using one group pretest-posttest design. The research instruments included five learning activity plans, learning achievement tests: pretest and posttest and a questionnaire on attitude towards environmental conservation. The results revealed that the learning activity entitled Life and Environment following sufficiency economy philosophy was effective at 81.67/82.92 which is higher than the 80/80 set-level, the students significantly had higher learning achievement after using the learning activity at the 0.05 level and the students significantly had a higher level of positive attitude towards environmental conservation at the 0.05 significance level.