Using the powder of soy sauce residue as raw material, the extraction and purification methods of soy isoflavone were investigated. An orthogonal design for the dynamic countercurrent extraction of isoflavones from soy sauce residue were tested at laboratory level. The optimized conditions were determined to be with 80% ethanol, soaked with a material to liquid ratio of 1:10 for 12 h before extraction. The extraction rate of total isoflavones was 0.35% with a content of 2.01% in the crude extracts. Using the low pressure chromatography and three kinds of macroporous resins, the purification of soybean isoflavones in the extracts was performed. A isoflavone product with a purity of 32% was obtained through NKA9 macroporous resin colomn chromatography. The method can be used for treatment of large numbers of samples within a short period of time，and the product can meet market needs of soy isoflavone.