Abstract: In the synthesis assessment of urban environmental qualities,there are a lot of factors impacting urban enviromental qualities.Each of them might play the defferent roles in the defferent layers.Generally,the relationship among them always is fuzzy.It is difficult to get a absolute result using general mathematics and even more difficult to compare the environmental qualities among several cities.In this paper,the mathematical model for multilayer fuzzy comprehensive judgements is applied to the synthesis assessment of urban environmental qualitie sin several layers.The result reflects the environmental qualities of defferent urbans in the subordinate level.