The invention discloses a method for purifying aescin from a semen aesculi extract. The method can comprise the steps that (1) sedimentation is conducted through acetone, specifically, the semen aesculi extract is dissolved through 3-5 times amount of low mass molecule alcohol, the acetone of the equal volume is added in a suspended status, stewing and sedimentation are conducted at 15-20 DEG C, and yellowish-brown sediment on the lower layer is obtained, decompressed and concentrated to obtain an aescin extract; (2) purification is conducted through macroporous adsorption resin, specifically, the extract is completely dissolved through 1-2 times amount of pure water, adsorption is conducted through the macroporous adsorption resin AB-8 with the sample loading quantity being 5g of the extract per 100 ml of the resin and the flow rate being 0.1-0.3 BV/h, elution is conducted through ethyl alcohol with the elution speed controlled to be 0.5-1 BV/h, and aescin flow is collected; and (3) washing and decoloration are conducted through acetone, specifically, the aescin flow is decompressed and concentrated, and obtained power is washed and decolored through the acetone, and subjected to vacuum drying to obtain an off-white aescin product. By adoption of the method, the aescin can be purified from the semen aesculi extract, and the method has the advantages that technological operation is easy and convenient, and the method is efficient and low in energy consumption, and meets production requirements of large-scale industrial extraction and purification of the aescin.