Since the second half of the twentieth century, more and more people around the world have consciously acknowledged the importance and urgency of protecting nature and our environment. Environmental ethics has been playing an important role of norms in the treatment of the relationship between human being and external environment, in economic development of every country, and even in our daily life. Therefore, whether environmental ethics is possible has already been out of question. However, in environmental ethics, the question how environmental ethics is possible, or the question how the possibility of environmental ethics is warranted, remains a pending question till now, and there is still substantial divergence and severe controversy today. To give rational answers to this question concerns not only the legitimacy of environmental ethics and its theoretical construction, but also the future and destiny of environmental ethical practice, i.e., the environmental movement.