With the quick development of urbanization, urban expansion has been paid more and more attention to by researchers from western countries and China. Here Wuxi City of China is selected as a case study. Located in the core-area of Changjiang (Yangtze) River Delta, as the sources of Chinese township enterprise, Wu culture, and national industry, Wuxi has experienced great change in the urban spatial structure, especially in the land use structure, and urban shape and scale. The ratio of industrial land was about one-third of the construction land in 2003.Residential and public infrastructure land had decreased a little from 1956 to 2003, but it remains to be the main construction land at present. Green land has increased at the highest speed due to the demand of sustainable development. After the reform and opening to the outside world, this kind of evolvement of urban spatial expansion is helpful for sustainable development. Economic development, transportation, and administrative planning are the main reasons for these changes. During different periods, the main drives are different. Economic development is the basic factor that influences urban expansion. Transportation influences urban evolvement in different times, but now the importance is not as great as 30 years ago, because administrative force plays an important function in urban planning of China and influences urban evolvement.