Aldo Leopold (1987-1948) was graduated from the Department of Forestry at Yale. He joined the U.S Forest Service in 1912, and became a professor of the Game Management at the University of Wisconsin since 1933. One of his work, 《A Sand County Almanac》,was published in 1949. Wallace Stegner once said: 「《A Sand County Almanac》 is regarded as 『the Bible of the conservation』, and Leopold is credited for a prophet of environmental conservation.] Curt Maine also commented that ＜The land ethic＞was the most significant essay in the 《A Sand County Almanac》. 【12】 ＜The land ethic＞ was originated from Aldo Leopold's concern about ecological degradation and environmental pollution. He criticized progressive economic utilitarian in America in early twentieth century. He suggested to rethink how to maintain harmonious relationships between men and land. Land ethic changes the role of human beings from conquerors of the land-community to plain members and citizens of it. It implies that a man should respect for his fellow-members as well as the community Aldo Leopold wrote down the point of the evolution-ecology. He also awakened that species should continue as a matter of biotic right, as well as obey and follow the rule and law in ecosystem. Inspired by the land ethic, the concept of a holistic 「ecocentrism」 is added into environmental ethics. Leopold was therefore widely acknowledged as the father of ecological conservation. The land ethic includes six parts: ethical sequence community concept ecological conscience - substitutes for a land ethics land pyramid land health and A-B cleavage.