Konjac glucomannan (KGM) is a natural soluble dietary fiber that is safe, biodegradable, and edible, with wide application in food and biomedicine. However, due to low plasticity and stability, KGM usually requires blending, physical, and chemical modification for production. Currently, deacetylated konjac glucan (DKGM) is used in food mainly as a food additive, food preservative, and health food. This review elucidates the KGM property changes before and after different deacetylation degrees, as well as the application progress and research status of DKGM in the food industry, with prospects for its development trends.