The invention discloses a method for improving the purity of 
acarbose. According to the method, impurities A in 
acarbose extracting solution are removed by an aluminum 
oxide chromatographic column. In the regenerating process, acid and base are utilized and organic solvents are not related, and compared with the traditional aluminum 
oxide regenerating process, the method has the following differences: the high-temperature activation is not needed, so that the 
process operation is simplified. According to the method, the impurities A in the 
acarbose extracting solution are removed by the aluminum 
oxide chromatographic column, and the high-purity acarbose 
bulk drug can be produced; the acarbose is purified by aluminum oxide, so that the content of the impurities A in the acarbose can be reduced effectively, part of pigments can be removed, and compared with the other method for preparing the high-purity acarbose, the method has the advantages that the purity of the acarbose is improved by 2%, the pigments in feed liquid are removed effectively, the safety and the stability of 
drug use of a patient can be improved finally. According to the method, the total yield is increased obviously, and the yield is high and is more than 88.95%.