city is an important product of the development of human civilization，as well as an important economic unit，residence and power space of human beings. With the development of economic globalization，industrialization，information technology and network，new forms such as megalopolis，megalopolis，megalopolis，global cities，metropolitan areas，urban agglomerations，global city-region and transcontinental metropolitan belts have emerged in human society. While these new forms of space provide a strong driving force for human economic development，they also bring many new problems and challenges such as administrative barriers，environmental pollution，social inequality，risk accumulation and so on，which put forward new demands for national and urban trans-regional governance system restructuring and governance capacity. Since the beginning of the 21st century，China’s urbanization process has been developing continuously，reaching 60% by 2018. The construction of metropolitan areas and city clusters has become an important strategic choice for the country to promote regional economic development. Therefore，this report，based on the needs of China’s practical development and with a global perspective，aims to systematically analyze and summarize the academic research trends and cross-border collaborative planning trends in the development of global metropolitan areas and city clusters since the 21st century，and to provide ideas and experience for the construction planning of metropolitan areas and city clusters in various parts of China.