Metropolitan tourism is a vital force in the development of regional economy and has become an important part of the research of tourism geography. But the formation mechanism and characteristics of change of metropolitan tourism system has yet to be well studied, which limits the depth of study on metropolitan tourism. Based on a literature review, this article examines the definition, organization, and drivers, mechanism, and processes of change of these systems. The conclusions are as follows: (1) Metropolitan tourism system is an open, dynamic, and holistic tourism region complex consists of attractions, destinations, facilities, media, transportation, as well as one or several agglomeration center cities within a particular geographic unit based on the material basis of regional urban system and ecological space. Such system has the characteristics of homogenous cultural origin, clear scale hierarchy, strong industrial connection, and zonal spatial differentiation.(2) Many external factors such as economic globalization, information technology, and traffic development have promoted the formation and development of metropolitan tourism. Meanwhile, tourism demand, tourism industry agglomeration, major events, regional tourism brand marketing, and government tourism cooperation have together promoted the formation and optimization of metropolitan tourism systems. Geographical proximity and attraction, impact of industrial production chain, administrative coordination, and cultural structure jointly promoted the spatial evolution of metropolitan tourism system , formed the polarization attract, convection, and balanced optimization development stages, and presented space development models of single center expansion, spatial linkage, and multistage network accordingly. The conclusion is of great significance for the understanding of metropolitan tourism system and subsequent research.