Water resource problems in Taihu basin became serious with the development of society and economy.In order to evaluate the water ecosystem services of Taihu basin and to provide a theoretical basis for watershed management,this study divided water resources of Taihu basin into seven districts based on the statistics data,land-use data and hydrological information,and then evaluated and analyzed the water ecosystem services and their spatial variability.The results show that the water supply volume of Taihu basin was 3.70×1010 m³/a,aquatic product yield was 6 681.180 t/a,transportation capacity of passenger and freight travel were 4.604×108 person/(km·a) and 2.90×1011 t/(km·a),respectively,water storage capacity was 4.53×109 m³/a,flood control capacity was 7.69×109 m³/a,carbon fixation and oxygen release rates were 4.28×106 t/a and 1.14×107 t/a,respectively,water purification capacity was 6.30×109 t/a,and sand transport and land reclamation rates were 1.22×106 t/a and 189.851 hm²/a,respectively.The total value of water ecosystem services was 9.10×1010 yuan/a.The order of various services in terms of value was as following,tourismtransportationwater storage and flood controlwater purificationcarbon sequensation and oxygen releasewater supplyaquatic productsand transport and land reclamation.The average ecosystem service value per unit area of Taihu basin was 19.22 yuan/(m²·a).The order of various districts in terms of average service value was as following,PuxiWuchengWest ZhejiangHangjiahuHuxiYangchengTaihu.