It is the aim of this paper to survey the history of philosophical environmental ethics in the United States of America. The backgrounds of the birth of environmental ethics are (a) traditional movement of environmental protection, (b) scientific research on ecosystem and ecology movements, and (c) warnings of global environmental crisis by natural scientists. Environmental ethics as philosophy was formed in the early 1970s against the background of these. From the mid-1980s to the present time, research, publication, and teaching in environmental ethics has rapidly expanded. Now environmental ethics is generally regarded as a field of applied ethics. But many of arguments with philosophical environmental ethics are theoretical, mainly metaethical. So we need to rethink the relation of environmental ethics and applies ethics thoughtfully.