Water　is　an　important　social　and　economic　resource　for　the　sustainable　development　of　mankind.　This　paper　measures　water　use　efficiency　(WUE)　of　106　cities　in　Yangtze　River　Economic　Zone　(YREZ)　of　China　during　2006-2017　based　on　undesirable　super-efficiency　EBM-DEA　model　which　takes　sewage　and　social　output　into　consideration.　The　results　show　that:　(1)　On　average,　WUE　(technical　efficiency,　TE)　of　the　YREZ　does　not　reach　efficient　level,　of　which　the　west　performs　best　among　the　three　regions.　Furthermore,　pure　technical　efficiency　(PTE)　in　the　middle　and　west　as　well　as　scale　efficiency　(SE)　in　the　east　is　constraint　factor　of　their　WUE　respectively.　(2)　WUE　in　most　cities　is　found　above　0.4,　and　in　a　few　cities　is　found　efficient.　(3)　It　must　be　noted　that　all　capital　cities＇　technical　efficiency　are　revealed　to　be　restrained　by　their　SE.　(4)　Whether　on　overall　level　or　regional　level,　WUE　has　been　decreasing　over　time　except　for　2017,　but　the　annual　decreasing　rate　is　becoming　smaller　and　smaller　and　even　convert　to　increasing　rate　in　2017.　(5)　The　change　of　WUE　mainly　depends　on　efficiency　change,　and　the　deceasing　of　it　should　be　attributed　to　technology　regress.　(6)　More　attention　should　be　paid　to　the　east　whose　total　decreasing　rate　is　largest　and　annual　decreasing　rate　fluctuates　greatest　over　time.　These　findings　may　provide　a　scientific　basis　for　further　studies　on　city　level　WUE　and　practical　water　resource　management　in　the　YREZ.