Highly acetylated starch was prepared by reacting corn starch with acetic anhydride. Acetylated starch (AS) is soluble in acetone and can be precipitated out from AS-acetone solution when deionised (DI) water is added as a non-solvent. The curcumin dissolved in AS-acetone solution could be effectively encapsulated in AS as spherical microparticles (1-3 mu m) when mixed with the DI water. The encapsulation yield of curcumin could reach 96.3%. AS encapsulation not only resulted in five-fold lower UV degradation rate of curcumin, the free radical scavenging activity of curcumin still could be well maintained. Approximately, 40% of the 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH center dot) was consumed by curcumin encapsulated in AS microparticles within 2 min.