Abstract: With the in-depth integration of urban management and new technologies such as spatial big data,5G and artificial intelligence,the applications related to new smart cities have become the key concerns of the geographic information industry field and society. This paper introduces the background and concept,theory and technology of smart city,describes the relationship among digital city,smart city and digital twin city,summarizes the current situation and trend of digital twin city,and discusses the smart city in the metaverse era. The budding period of smart city relies on spatial information technology,database technology,virtual reality technology and computer network technology to build digital city,the development period integrates artificial intelligence technology,Internet of Things technology,cloud technology and spatio-temporal big data technology on the basis of digital city to build new type of smart city,and the construction period combines new type of smart city related technology and realistic 3D technology to realize digital twin. The cross-era metaverse smart city may integrate technologies or devices such as augmented reality,extended reality,brain-computer interface and somatic devices on the basis of the digital twin to realize the beautiful vision of human living in an amphibious world.

Key words: digital city, smart city, digital twin city, metaverse era, intelligent organism