A method for processing purified konjac flour comprises twelve steps of material selection, swelling, extraction, material placing in a low temperature oxygen-free room, grinding, dehydration, dehumidification drying, dry grinding, winnowing, sieving, checkout and homogeneous warehousing. The method for processing the purified konjac flour has the advantages that the swelling and the extraction can enable impurities in the konjac flour to be soluble in impregnation liquid and accordingly separated out, the activity of polyphenol oxidase can be restrained and brown stain can be prevented through processing in the low temperature oxygen-free room. Starch and the impurities attached to glucomannan particles can be further peeled off through the grinding, and then the impurities are removed through the dehydration. Heating can be avoided and brown stain, gelatinization and adhesion can be prevented through the dehumidification drying. By means of the grinding in the low temperature environment, the ragility of konjac particles can be improved, the impurities can be easily separated, and small particles can be obtained. Various levels of purified konjac flour meeting the national requirements is obtained after the sieving. Therefore, produced purified konjac flour does not contain sulfur, is free of brown stain, gelatinization and adhesion and is pure white, and the product quality is improved.