Henry David Thoreau, who was ignored and dismissed by his contemporaries, now has become a global figure as the saint and pioneer of environmental protection. This study intends to explore Thoreau’s life philosophy on man and nature encountering the industrial civilization, which he believed caused the life alienation of nature and human beings. In his reflection on industrial civilization, Thoreau inquired into the rationality of science and technology, recognized the exploitation of life under the guidance of rationality and objected to the material culture in which people’s lives were eroded and degraded. Beneath his fierce critiques, there is a great concern about the existence and development of the whole universal life. He tried to find an ideal solution to the crises of natural ecology and spiritual ecology of human beings. His critiques on industrial civilization and his cosmological beliefs of life are still enlightenment for the alienated people of today. The author thinks that Chinese people could also gain some revelation from Thoreau’s life philosophy. Firstly, it stimulates us to rediscover and reinterpret the Chinese classics, which have been ignored in China in the past 100 years, and to find our own eco-wisdom; Secondly, it forces us to reflect on China’s development of modernization.