The invention relates to a method for preparing high-purity soybean saponin A and soybean saponin B by high-speed countercurrent chromatography, which comprises the following steps of: (1) selecting a solvent system which is provided with a fixed phase as an upper phase and a mobile phase as a lower phase and has four components with the volume ratio of 1-5 to 0.5-1 to 1-5 to 5-10; (2) using the fixed phase to fill a countercurrent chromatographic column, regulating the rotation speed of a host to be 600 rpm to 1000rpm and pumping the mobile phase into the column at the flow rate of 0.5 ml/min to 4ml/min; (3) after the whole system is in dynamic equilibrium, introducing samples through an introduction valve; and (4) receiving a target composition according to a UV atlas of a detector, compressing, freezing and crystallizing the fraction to obtain monomers of the soybean saponin A and the soybean saponin B. The soybean saponin A and the soybean saponin B prepared by the method can reach quite high purity and the preparation method has simple operation, high separation efficiency, great separation volume, high recovery rate and good repeatability.
