Through the introduction of fuzzy mathematics theory into water quality evaluation of wetland ,the paper set up a evaluation system suitable for Xixi wetland. Making use of fuzzy comprehensive evaluation method ,it comprehensively evaluated the monitoring results of water quality in Xixi wetland from 2009to 2011．The results indicated that the water quality of Xixi wetland in 2009was slightly better than that of other two years, that of Shentankou, Qiuxue''an, Baijialou and Shuimaoshichang belonged to level III or IV but that of Yanshanhe and Jiangcungang to level V. The water quality of all the researched points was level V from 2010to 2011,which indicated that the water pollution of Xixi Wetland was serious and the main exceeding factors were TN, TP and dissolved oxygen.