Abstract: The removal of acetyls from konjac glucomannan (KGM) can modify the molecular structure via a molecular modification method by mechano-chemical treatment to increase the film performance of the KGM in engineering. The de-acetylation from the KGM was performed with potassium hydroxide (KOH) as a modifier through a mechano-chemical treatment in a high energy intensive vibrating mill. The results showed that the mechano-chemical treatment was an effective modification method to remove the acetyls from the KGM. The removal rate of acetyls from the KGM sample could be 90 % when the KGM sample was treated by this effective mechano-chemical method for 30 min. The mass loss of de-acetylated KGM sample was lower than that of original sample. The de-acetylated KGM samples possessed a better swelling rate and a stability in water.