Because cherish the natural land，there is still nearly 80% of ecological land in the Ile-de-France while it achieve a high urbanization level. Farmland which constitute nearly half of the area of Ile-de-France，enhance the diversity，livable，attractive and sustainable development capacity of Paris. It also brings Paris strong natural foundation and development advantages superior to other global cities. Île-de-France 2030 regards agriculture as an important advantage and an integral part，and considers the function of agriculture in the development in many aspects of the whole region development. It proposes to retain agriculture，to promote agriculture sustainable development，to drive agriculture to diversify，value added and transformation. These ideas have important reference for China’s metropolis. Mega cities in China should also rethink the function of agriculture in the whole city system，protect farmland and agriculture，and promote agriculture and city harmonious coexistence and collaborative development.