Abstract: In this paper, based on lots of measured information, the correlation dimension has been extracted from time series of ground behavior such as displacement and penetrating water quantity (seepage property) etc. The process of deformation failure for coal floor strata is influenced by mining on pressure-bearing water, and its movement character has been studied. The analysis of actual examples indicates that the typical chaos has been demonstrated in the process of deformation failure for floor strata. In addition, because number of the correlation dimension of the seepage target for floor strata is larger than that of the displacement target, it is indicated that the seepage target is more sensitive than the displacement target when it is used to describe the deformation failure character of floor strata.