Abstract: On the occasion of the 2 centenary of Engels' birth, it is of great significance to make an in-depth study of his book Dialectics of Nature. Engels' Dialectics of Nature not only reveals the dialectical unity between man and nature, but also scientifically predicts that the infinite demand of human society on nature will lead to the ecological crisis. The new era of Xi Jinping's ecological civilization thought of “harmonious coexistence between man and nature” and the theory of “two mountains” is the core proposition of Engels' Dialectics of Nature and is the succession and development of the ecological thought. Engels'dialectical picture of the harmonious development of man and nature and the theory of ecological thought are the important resources of Xi Jinping's ecological civilization, are the concrete practice of “Chinese Approch” and provide the important theoretical guidance for Xi Jinping's ecological civilization in the new era.