The Evaluation of water quality is one of the important aspects of water resource management. Many indicators are needed to be considered in the evaluation process and thus the water quality evaluation problem is actually a Multiple Attribute Decision Making (MADM) problem. The aim of this study is to put forward a new water quality evaluation method based on grey analysis method. In order to avoid the subjective randomness on the weight of each evaluation indicator, the coefficient of variation method is adopted to determine the attribute weights of water quality evaluation. A practical example is given to illustrate the effectiveness and feasibility of the proposed method.