为了科学地制定城市居民用水定价，以水价改革目的为指导，根据城市居民用水定价原则，结合需求弹性相关理论，建立基于正态分布假设的城市居民用水阶梯水价计量模型并给出模型的评价标准，对城市居民用水的不同阶梯定价模式进行评价。以北京市2004年水价听证会上提出的城市居民用水阶梯水价方案为实例进行研究，得出1∶3∶5的阶梯水价是更优的结果。进而对其它阶梯水价方案进行了进一步分析和论证，给出二级与三级阶梯水价级差对实现水价改革目标的不同作用，最后对城市居民用水定价提出相应的对策与建议。

In line with the principles of urban water pricing and under the uideline of water price reform, this paper applies the theory of demand elasticity to establish an econometric model of multistep water pricing for urban residents based on normal distribution hypothesis, and further works out the evaluation criterion, which can be used to assess various multistep water pricing modes so as to scientifically determine the price of urban household water consumption. The multistep water pricing proposed at a public hearing on water price for Beijing residents in 2004 is taken as a case study, and the study shows that the price ratio of 1∶3∶5 based on three grades of water consumption is better. Other modes are further analyzed and concluded that the water price difference between the second and the third grade has different impacts on water price reform. Finally, corresponding measures and advices on urban water pricing are given.