The purpose of the study was to review ecosystem service researches and show the trend to guide researchers who want to study ecosystem service. Ecosystem service has been a theoretical base for conservation of nature such as grand mountains, rivers and so on. Moreover, reviewed studies showed economical, social, environmental values of ecosystem service in nature as well as in urban to support ecosystem service theory. By leading metropolitan governments in America, Canada and european and asian countries, the urban tree canopy(UTC)s’ ecosystem services have been evaluated quantitatively and accumluated as urban forestry data. This global trend has an implication that the study of UTC and its ecosystem service can support the provision of urban forestry and green spaces and especially, Korean cities should realize UTCs’ values on ecosystem services and start to apply them institutionally to enhance their urban environment.