Abstract: From the scientific perspective of Xi Jinping Thought on Ecological Civilization, the modernization of forest and grassland is an important part and task for the modernization of harmony between humanity and nature. It is a process of realizing the transformation of forest and grassland from their traditional forms to their modern forms in accordance with the principle of ecological civilization, in order to maintain and enhance the sustainability of the forest and grassland ecosystem. It is a scientific choice to act on the grand historical view that “when forests and grasslands flourish, civilization thrives”, to give full play to the comprehensive value that “forests and grasslands can help conserve water, bring in economic benefits, boost grain production, and serve well as a carbon sink”, and to adhere to the confidence of “socialist ecological civilization”. The modernization of forest and grassland can be carried out smoothly only by following the principles of putting the people first, emphasizing new development concepts and systematic ideas, and adapting to local conditions. In addition, it is essential to start from vigorously protecting the forest and grassland ecosystem, developing the forest and grass economy, and strengthening the improvement of forest and grassland. The development of the modernization of forest and grassland is the basic project and important task to ensure the sustainability of Chinese modernization.