The 1st China International Import Expo (CIIE) was held in National Exhibition and Convention Center (NECC), Shanghai, in November 2018. The hydrodynamics of river network in CIIE area is weak, and the pollution discharge into river is heavy, especially the Xiaolaigang river just divorced from malodorous black in 2017. It’s quite essential to improve the water enviromment in CIIE Area. Water enviromment improvement schemes were studied based on numerical simulation and field test. Pollution intercepting, ecological restoration and hydrodynamic improvement were adopted to slove the problem of bad water quality, water turbidity and weak hydrodynamics in CIIE area. Three fabricated downflow weirs were built to form cascade water level and water circulation, promoting the ecological restoration and hydrodynamic improvement. The result of operation monitoring indicated that the transparency of the Xiaolaigang river core area was greater than 1.5 m, and the transparency of key area was greater than 1.2 m. Main water quality indicator was promoted from Ⅴ- exceed Ⅴ to Ⅱ-Ⅲ. Effect evaluation indicated that pollution intercepting played an important role in water environment improvement, about 73% proportion. The proportion of hydrodynamic improvement and ecological restoration in water environment improvement was about 15% and 12%.