The removal of the colloidal impurities in the purification of salvianolic acid B (SB) was carried out on a macroporous adsorption resin column with a modified elution method on the principle of combining frontal chromatography with displacement chromatography. Two serially connected columns were packed with macroporous adsorption resin in a certain proportion. The latter column was eluted with 50% methanol, when the colloidal impurities reached saturation adsorption in the former column. Comparative study suggested that the SB product was superior to that from the routine method with the weighted average purity risen from 59.6% to 64.5%, and the recovery from 69.75% to 80.0%. The ethanol concentration was lowered in the eluent. The method is simple and can be used for the production of SB in large scale.