Abstract: According to the concept of ecosystem health, the index system of urban ecosystem health was set up by using the frame of pressure, status and response. The principal components method was used to find out main indexes with their weights assessed. Then Fuzzy optimal assessment model was used to predict the trend of system development, which could avoid the problem of unknown standard value of index in other researches. Combined with urban planning targets，the model could be effectively used to assess the urban ecosystem health. As a case study in Shanghai, the results showed that Shanghai urban ecosystem health had been improved during the years of 1995 to 2000, indicating that the development of environment, society and economic became harmonious, while some of the indexes were bad and a gap still existed between the current status and the expected of the system.

Key words: urban ecosystem, health, assessment