Abstract: The comprehensive assessment of water environment for urban stream(WEUS) aims at providing the essential information for its restoration.Starting with the idea of environment, this paper analyzes the concept of water environment of urban stream and its connotation.To fit for the objective of stream restoration, the index system, including morphology, hydrodynamics, water quality, zoology and landscape, is established, and the fitting assessment model is put forward.Furthermore, the above theory and method are applied to the case study of 6 representative reaches of the Ancient Canal in Zhenjiang city, and some suggestions are provided for the next restoration based on the result of evaluation.