The modernization of “harmony between man and nature”, a perfect combination of Marxism and Chinese excellent traditional culture, is to adapt Marxist ecological thought to the Chinese context and the needs of our times. It not only constitutes the philosophical foundation of Xi Jinping ecological civilization thought, but also reflects the essential characteristics of the new path to modernization at the ecological and cultural levels. Underpinned by the psychology of “harmony between man and nature”, Xi Jinping, General Secretary, gives a systematic and scientific interpretation of the relationship between ecological civilization and economic development. Thus Chinese modernization of “harmony between man and nature” integrates the two in the practical field, which fundamentally transcends the western ecological civilization and western modernization. Under the scientific guidance of Xi Jinping Thought on Socialism with Chinese Characteristics for a New Era, the Marxism of the 21st century, China has opened up a new path to modernization by pursuing harmonious coexistence between man and nature. It shows unprecedented historical significance in the world: while solving the ecological problems on its journey to socialist modernization, China, based on common interests for mankind, has proposed a solution to global ecological problems, which provides a practical path to modernization for other countries in the world, especially the vast majority of developing countries.