Karst collapse is widespread in the coal field of northern China, which takes a serious influence on the designing and production of mine well. On the basis of establishing the forward model, this article made use of migrate result of model data to extract and analyze the seismic attribute. Some analysis and contrast indicate that the lateral scale of karst cave reacts well in the attributes of amplitude class, frequency class, and phase class. The vertical scale can be quantitated by the spectral decomposition attribute.