Abstract: The urban ecosystem is a composite artificial ecosystem, and the urban ecological suitability is a significant symbol of development of economy in regional society. This paper presents the indicator system of urban ecosystem suitability from the five aspects including resource degradation and supporting capacity of main city zone, environmental condition and pollution load of main city zone, efficiency benefits of main city zone, social security and social welfare of main city zone, and ecological support of city zone. In allusion to the “reverse ecology” issues in the process of development of cities. On that basis, fuzzy inference and pattern recognition methods were adopted to set up a model of evaluation for urban ecosystem suitability and utilized this model to evaluate the urban ecosystem suitability of Yangzhou during 1997—2007. It was found that the evaluation value of Yangzhou city during 1997—2007 was between 0.437—0.634 which was in normal and good range, and the overall urban ecosystem suitability appears rising.