Abstract: Fuzzy evaluation method can quantify fuzzy issues in water quality evaluation, and can thus evaluate water pollution levels more accurately and scientifically. On the basis of existing researches in water quality evaluation, Hamming Distance Fuzzy Assessment Method, a kind of brief and feasible method, was selected for groundwater quality assessment of three municipal solid waste (MSW) landfills in Beijing. The assessment results were compared with those by other methods such as conventional fuzzy comprehensive evaluation method. The results of Hamming Distance Fuzzy Assessment Method showed that the groundwater quality levels of three MSW landfills were Ⅳ, Ⅳ and Ⅲ, respectively, which was almost consistent with the conclusions by other four methods including conventional fuzzy comprehensive evaluation method. The results showed that Hamming Distance Fuzzy Assessment Method was feasible for groundwater quality assessment of MSW landfills and the assessment results were reliable. The groundwater pollution degree could be characterized by further contrasting the values of Hamming distance under the same groundwater quality level, which demonstrated that the method had a high resolution.