With the rapid development of social economy in China since the reform and opening up, the process of urbanization is speeded up. Urban spatial expansion is one of the notable features of urbanization, analysis of urban spatial expansion have a great benefits to predict, guide and regulate the future development of the city, analyze and settle the problems in the city's social and economic development. This paper takes Wuhu City as an example, which is located in the southeast of Anhui province, Central China. There has been a rapid development in its urbanization and obvious changes in the urban spatial expansion since the reform and opening up. To reveal the dynamics of urban spatial expansion, Landsat MSS/TM/ETM+ remote sensing images in different period were used as data resource, with the help of RS and ArcGIS software platform, the spatial expansion information of Wuhu City was extracted by man-machine interactive method from multi-temporal satellite. Then select some indexes such as speed of urban spatial expansion, expansion intensity, compact ratio, fractal dimension, center coordinates and elasticity coefficient and use some different research methods, for instance spatial form analysis, overlay analysis, fans analysis, the temporal and spatial expansion characteristics of Wuhu City as well as their driving forces were systematic analyzed. The result shows that during the period from 1979 to 2012, the overall pattern of urban spatial form of Wuhu City is from compact and stable change into loose and unstable.