The application scope of classical famous prescription Xiayuxue Decoction was discussed and expanded based on the analysis of the formula indications. It is thought that blood stasis is the cause of indications of Xiayuxue Decoction， and blood stasis stagnating in the lower energizer is its pathogenesis， which should be distinguished from general blood stasis. The connotation of the Decoction can be explained from four points： firstly herbs with drastic downward-expelling effect can attack blood stasis and herbs with stasis-breaking effect can promote the generation of new blood； secondly the orderly ascending and descending movement of herbal action can dredge collaterals； thirdly the combination of herbs with drastic and mild properties， reducing and nourishing functions can neutralize the strong attacking-expelling side effect； and fourthly the worm medicine can penetrate deeply into the place where the pathogen ambushes. One proven case is provided.