聚焦自然本底和人类活动的双重影响，从水资源、生态环境和经济社会3个子系统出发构建水环境承载力评价指标体系，进而建立一种基于可变集方法的水环境承载力指数模型，探讨长江经济带水环境承载力的时空变化特征。结果表明：2009—2018年，长江经济带水环境承载力呈现逐年提升的基本发展态势，承载力指数由4.20增至6.08；上、中、下游区域的水环境承载力日趋均衡。3个子系统承载力则具有空间分异特征：上游区域的生态环境子系统相对较弱，但差距逐年缩小；中游区域的水资源子系统恶化趋势明显；下游区域的经济社会子系统常年显著占优，而水资源子系统则严重滞后。2018年，长江经济带的水环境承载力具有明显的空间分布规律，除浙江外，表现为上游优于中游、中游优于下游，但总体上呈现经济社会子系统绝对占优、生态环境子系统一般、水资源子系统相对滞后的基本特征。水资源子系统是当前长江经济带水环境承载力提升过程中需要重点关注的主要矛盾点之一。

Yangtze River Economic Belt (YEB) is one of the important strategic development regions in China which has created more than 2/5 of China′s GDP,but it faces the conflicts between economic development and water environment protection.With the rapid development of economic-society,human activities have more and more impacts on the water environment,therefore it is of great significance to study the water environment carrying capacity (WECC) of this area,in which the spatial-temporal variation of WECC are an important content. In most previous related studies,some method are usually used to determine the grade of WECC.In fact,WECC is a fuzzy concept,and the boundary between two adjacent grades is not clear.Therefore,it is necessary to consider the law of unity of opposites between adjacent grades in the evaluation of WECC.Variable set method is an important uncertainty mathematical theory in the field of water resources system analysis.The variable set method is used to calculate the relative membership degree,and the index based on grade eigenvalue is used to characterize the state of WECC.Focusing on the dual effects of natural background and human activities,the evaluation index system of WECC is constructed from the three subsystems of water resources,ecological environment and economy and society,and a water environment carrying capacity index (WECCI) model is established based on variable set method,and the temporal and spatial variation characteristics of WECC in YEB are discussed. The results show that the WECCI of YEB increased from 4.20 to 6.08,showing a basic trend of increasing year by year;The WECCI in the upper,middle and lower reaches is becoming more and more balanced,the variance decreased by 57.27% from 0.14 to 0.06,but increased slightly in 2018;The constraints have spatial differentiation characteristics;The ecological environment subsystem of upper reaches is relatively weak,but the gap is narrowing year by year;The restriction of water resources subsystem in the middle reaches is becoming more and more prominent;The economic-society subsystem of lower reaches maintains significant advantages all year round,while the water resources subsystem lags behind seriously;In 2018,except Zhejiang,the WECC showed that the upper reaches were better than the middle reaches,and the middle reaches were better than the lower reaches.According to the provinces(manicipalities),Zhejiang,Sichuan,Chongqing,Yunnan,Guizhou,Hunan,Jiangxi,Hubei,Jiangsu,Shanghai and Anhui were ranked from high to low. The WECC of YEB has improved year by year from 2009 to 2018,and has an obvious spatial distribution law;The water resources subsystem has a significant restrictive effect on the improvement of WECC of the current YEB and become one of the main contradictions that need to be paid attention to in the process of improving the WECC of YEB.Analyzing the temporal-spatial variation and main interference factors of WECC of YEB and its region can provide reference for the formulation of sustainable and high-quality development policies of YEB.