Urban green space is important to maintaining ecosystem stability and improving the urban environment,and is also vital for public health.Assessing the value of urban green ecosystem services is crucial in increasing life quality of urban dwellers,and working towards a sustainable future.This study assessed and analyzed the value of urban green ecosystem service in Nanchang city during 1998-2011 based on a mixture of a survey and literature study.The main objective of this study was to present an assessment approach for ecosystem services in an urban green space.A set of indicators representing important urban green space ecosystem services-local climate regulation,air cooling and noise reduction was tested using survey data and literature data.The results showed that:(1) The ecological regulation service of urban green space increased by 230 million Yuan during 1998-2011,with an average annual growth rate of 10.78%,but the value of green space ecosystem service per area fell slightly.(2) Various kinds regulation service values were sorted as follows:oxygen releasing>noise reduction>temperature reduction>carbon consequence>dust detension>NO_X absorbtion>SO_2 absorbtion.(3) Fixation and absorption capacity of CO_2 and SO_2 was far less than its total industrial CO_2 and SO_2 emissions in Nanchang urban green space.Although industrial dust emissions were less than the amount of green space absorption in recent years,industrial waste gas emissions grew by an average of 10.49% per year, which was the key cause of the formation of haze weather.Regulation service functions of urban green space, such as carbon consequence and oxygen releasing,can compensate by appropriation of vast green areas of ecosystem services provision beyond the city boundaries,which include nature reserves,forest park,shelter forest, economic forest,water conservation forests,timber forest and other natural forests of near by suburban county, but other regulation functions such as cooling,noise reduction,SO_2 and NO_X absorption can not transfer from one area to another area.Therefore,the government can aim at both increasing carbon sinks and decreasing CO_2 or NO_X emissions with proper land-use planning.The efficiency of ecological regulation functions in cities could be improved by increasing green coverage,diversifying species composition,planning plant structure,and providing sound green space management,which can improve the sustainability of urban ecosystems and the quality of urban residentslife.Development of urban green space management should take scale,heterogeneity,management intensities and other social and economic co-benefits into consideration.Green area of urban regions plays a role in climate change mitigation.The impacts of climate change coupled with urban land-use and land cover change will bring serious challenges to maintaining ecosystem services in urban areas.