Abstract: The Wavelet theory which concentrates on the multiresolution signal processing is nowdays considered to be such a greaty potential theory. Image Processing with the pyramid structure、image understanding and a modern GIS which should have the multiscale function need this theory to support. This paper proposes a new kind of image representation——Wavelet Representation by using Wavelet Transform,improves Wavelet Transform with an arbitary direction,and employs it to extract the building/shadow edges from the aerial im-ages. This wavelet representation in computer vision and image analysis typically helps in two ways:1)allowing ths most economical resolution to be used for each of several image features or objects to be treated; 2) making certain hierarchical structure in an image more explicit and easier to use. The experimental results illustrate this approach is feasible.