The global climate and environmental change, as well as the development of urbanization, have had a great impact on the urban environment. The development of green, digital, and “dual carbon” policies has brought great development momentum to the development of green cities. However, at present, the research and practice of green cities in China are not mature. In order to promote the development of green cities, the article compares the construction of green cities in China and Korea and summarizes the construction experience of Korea at different levels of green city development, especially in terms of policies, technology, green technology facilities, and green buildings. The direction of green city construction in China is from four aspects: the construction of China’s urban green space system, the green renewal of urban space, the construction of urban green infrastructure, and the development of urban green buildings. This will serve as a feasible path for the development of green city construction in China and provide reference suggestions for building sustainable and healthy green cities.