Abstract：In spite of the extreme significance of connectivity rate of discontinuities for rocks，the method for estimating connectivity rate had not been put forward until H-H probability model was introduced in 1998，based on the intersectant probability between discontinuities and window measured. However，H-H probability model requires that discontinuities should be distributed homogeneously and the distance between discontinuities should be shorter than the length limited by size effect. In order to overcome these disadvantages，an equivalent model for distribution of discontinuities is built. On the basis of this equivalent model，the generalized H-H probability model of connectivity rate estimation is deduced. In order to test its correctness，it is used to calculate connectivity rate of discontinuities for sideslip surface in a large hydropower project in southwest China. It is showed that the connectivity rate estimated by this method agrees wel with the measured one.
