鉴于湘江流域独特的区域位置及经济地位，且由于江河上游城市的污染产出会影响下游城市的环境表现，结合非期望投入-产出提出改进的RAM-Undesirable模型和Global-Malmquist指数来测算湘江流域城市群河流环境效率。研究发现: (1) 湘江流域城市群河流总体环境效率相对稳定且逐步改善，但区域内差异明显；(2)考虑非期望投入可以消除河流流动性及初始水质差异造成的误差，从而更客观地反映效率水平；(3)各城市河流的效率变化和技术变化发展不平衡，存在互补现象，其中技术变化是导致全局Malmquist指数波动的主导因素。

Due to the unique regional location and economic status of the Xiangjiang River Basin, and the pollution output of the upstream cities will affect the environmental performance of the downstream cities, therefore, this paper combines the undesired input-output to propose an improved RAM-Undesirable model and the Global-Malmquist index to measure the river environmental efficiency of the Xiangjiang River Basin urban cluster. The study finds that: (1) The overall environmental efficiency of the Xiangjiang River Basin urban cluster is relatively stable and gradually improved, but the regional differences are obvious. (2) Considering the undesired input can eliminate the error caused by the river fluidity and the initial water quality difference, thus reflecting more objectively the level of efficiency. (3) The efficiency changes and technological changes in urban rivers are unbalanced and there are complementary phenomena, among which technological change is the dominant factor leading to fluctuations in global Malmquist index.

F127

湖南省哲学社会科学基金青年项目“基于耦合视角的湖南省新型城镇化与乡村振兴协同发展研究”（18YBQ042）；湖南省自然科学基金青年基金项目“中国国家公园内的社区参与机制研究：以湖南南山国家公园为例”（2019JJ50142）；广东省社会科学基金项目“广州市现行排水管理模式下水体污染治理模式研究”（ 2018SSKXH05003）