Based on the investigation and analysis of water quality and water environment situation, the impacts of the project of expressway from Jiekou to Liangkou on water environment were analyzed and predicted.Especially the impacts on Liuxi River had been investigated in detail.By appraising, present quality of Liuxihe was good and met the demand of water environment function.The impact on water environment by the two large bridges in this project is important and was emphatically analyzed.Result shows that the impacted range is within 100m and 150 m downstream respectively.During operation period, negative impact on water-environment could be slight and lightened by adopting some environmental protection measures.