TECHNOLOGY FOCUS - BIOLOGY - Preferred Method: The aqueous solution of the fenugreek saponin extract passes through polyamide column or alkaline alumina column. The aqueous solution of the fenugreek saponin extract passes through the alkaline alumina column, the collected and combined eluent passes through polyamide column, and the effluent liquid is collected, concentrated and dried. The column is washed with water until the eluent is vibrated and free from foam or one part of eluent is added (0.8-1.2 times the volume of perchloric acid) to show red color. The method further comprises: (b) purifying the crude product (I) of fenugreek saponin B by passing the eluent through a D101 type macroporous resin column, washing the macroporous resin with water until the eluent is clear, eluting using ethanol solution (75-85 wt.%), collecting and combining the eluent alcohol solution, recycling solvent and obtaining the extract, where the extract is the crude product (II) of the fenugreek saponin B; (c) purifying the crude product (II) of fenugreek saponin B by adding water and dissolving the extract, extracting using n-butyl alcohol, recycling n-butyl alcohol and drying to obtain the white powder, which is the crude product (III) of fenugreek saponin B; (d) purifying the crude product (III) of the fenugreek saponin B by dissolving the obtained white powder in methanol, adding acetone to precipitate until there is no precipitate separated out, filtering and drying the precipitate, dissolving the precipitate using methanol, absorbing using silica gel H or silica gel, removing solvent and grinding; (e) taking the silica gel H, packing column using chloroform-methanol-aqueous solution in a volume ratio of 23-27:5-7:0.5-0.9 by wetting process, eluting using chloroform-methanol-aqueous solution in different ratio, collecting a part of chloroform-methanol-aqueous solution in a volume ratio of 23-27:5-7:0.5-0.9, recycling the solvent and drying to obtain the crude product (IV) of the fenugreek saponin B; and (f) purifying the crude product (IV) of fenugreek saponin B by dissolving the crude product (IV) of fenugreek saponin B in water, passing through a Sephadex LH-20 (RTM: Cross-linked dextran based resin), eluting using chloroform-methanol solution in the volume ratio of 1:1, and collecting the eluent; or dissolving the crude product (IV) in water, passing through a C18 reverse phase silica gel column, eluting with water and methanol solution in a volume ratio of 1:1, collecting the eluent, super-filtering the eluent or filtering using No.3 sand type core funnel, collecting the filtrate, and drying to obtain the fenugreek saponin B. In the step (b), the eluent alcohol solution is eluted with perchloric acid and evaporated to dryness until no color is seen. In the step (c), the extraction is carried out using n-butyl alcohol used for 4-6 times, combining the extracted liquids, and recycling n-butyl alcohol, where the volume ratio of n-butyl alcohol used for extracting for each time and the aqueous solution of extract is 0.7-1.3:0.7-1.3. In the step (d), the silica gel H is used for absorbing. Preferred Components: The concentration of the total fenugreek saponins in the aqueous solution of the fenugreek saponin B extract is 70-130 g/l. The amount of ethanol solution used for eluting is 80 wt.%. The volume ratio of chloroform-methanol-aqueous solution for packing column is 25:6:0.7. The volume ratio of the chloroform-methanol-aqueous solution for gradient elution is 25:12:2.