To explore the best purification method by observing effects of different purification ways on the extractive rate of salvianolic acid B in Salvia Miltiorrhiza Bge water-extraction. Methods: Salvianolic acid B content and dry extract yield rate were used as indexes for assessing the best purification method among ethanol precipitation, high speed centrifugation and macroporous resin absorption. Results: Among all three methods, salvianolic acid B content by macroporous absorption resin was the highest, with dry extract yield rate being the lowest; salvianolic acid B content by ethanol precipitation was the lowest, with dry extract yield rate being the medium level; and salvianolic acid B content by high speed centrifugation was at the medium level, with dry extract yield rate being the highest. Conclusion: Water extraction of Salvia miltiorrhiza Bge by macroporous absorption resin is considered as the best purification method.