Urban planning is the integration of the disciplines of land use planning, transport planning, environmental planning. Urban planning should satisfy the survival demands of humans and also it should be in harmony with the natural conditions. As the concept of sustainable development accepted by more and more people, urban renewal and re-generation of inner cities have become very important parts of the city's constructions. In the process of re-building inner city, the first step is to evaluate the old urban zone clearly and objectively.Affected by the limits of the exiting evaluation system, we can hardly tell the difference between the city plans which have similar indices such as land utilization rate, building density and plot ratio etc. With the aid of fractal and multi-fractal theory, we analyzed the features of the satellite images of two cities and attempted to find the difference between them.