Abstract: Das Capital is a magnificent and epoch-making work, which contains rich ecological ideas. From the man-nature and man-man relationships, Marx criticized the anti-ecological nature of capitalist mode of production and constructed the basic framework of his ecological thoughts. Marx believes that there is a dialectical unity between man and nature. Labor plays an important role of media in the relationship between man and nature. The capitalist mode of production has caused the alienation of labor and has also led to the alienation between people. Only if the capitalist private ownership has been eliminated, could a true harmony between man and nature and between people be achieved. The ecological thoughts contained in Das Capital have important value for guiding the construction of ecological civilization in China's new era. Xi Jinping's ecological civilization thoughts in the new era are the inheritance and development of the Marxist ecological concept, and reflect the concrete practice of Marx's ecological thoughts in contemporary China.