Abstract: Ecosystem service flow is an effective way to explore the supply and demand of ecosystem services. It has played an important role not only in revealing the dynamic process of the flow of ecosystem services from natural ecosystems to human society, but also in clarifying the quality, direction and distribution characteristics of ecosystem services. From the perspective of connotation, theoretical framework, model and application of ecosystem service flow, this study systematically reviewed the research progress of ecosystem service flow, based on the selected 183 SCI papers and 33 domestic core journal papers by using CiteSpace visualization software. The applicability and applications research of relevant models and methods have been summarized, and the shortcomings of existing studies and future research directions are discussed. The results show that there have been some important progresses on the study of ecosystem service flow, mainly including the concept discussion of service flow, model applications, quantification of service flow, ecosystem service supply and demand assessment, ecological compensation, ecological restoration, and security pattern optimization. While there are much less progress on researches of general framework exploration, assessment model, index system selection and multi-scale study. In the future, it is necessary to strengthen the studies on the application of ecosystem service flow in ecological protection and policy design, the establishment of a general research framework of ecosystem service flow. The development and calibration of models, the study on ecosystem service flow in key regions with multi-temporal scales, the optimization of ecological security pattern, ecological compensation and ecological restoration, so as to provide important scientific basis for the formulation of regional ecological protection and management policies.

Key words: ecosystem service flow, ecosystem service supply and demand, ecological model, ecological security pattern, CiteSpace