In this study, the effects of acetylation on the swelling and enzymatic degradation of maize starch as well as the release rate of drug from tablets coated with starch-based polymer were examined. Maize starch acetates (SA) were prepared by acetyl esterification with a degree of substitution from 1.31 to 2.40, and bovine serum albumin was used as a model drug. For in-vitro drug release assays, the starch based polymer was incubated in simulated gastric fluid, simulated intestinal fluid and simulated colonic fluid, respectively. The resistant starch content and swelling property of maize starch were increased by acetylation, which retarded its enzymatic degradation. Drug release studies have shown that SA-coated tablets could deliver the drug to the colon. These results suggest that the SA can be used for a potential drug delivery carrier for colon-targeting biomacromolecule drugs.