The structure and properties of cellulose acetate (CA) prepared by homogeneous acetylation in ionic liquids (CA(Homo)) and heterogeneous acetylation (CA(Hete)) were investigated. The characterizations of CAs such as molecular weight, molecular weight distribution, degree of substitution (DS), distribution of acetyl groups and the partial DS at C-2, C-3 and C-6 were determined by GPC, H-1- and C-13-NMR. The DS of CA(Homo) and CA(Hete) was about 2. 50 calculated by H-1-NMR. The distribution of acetyl groups calculated by C-13-NMR was C-6 > C-3 > C-2 for CA(Homo) and C-3 > C-2 > C-6 for CA(Hete), respectively. In addition, the structure of CA(Homo) had better uniformity than that of CA(Hete). Subsequent property studies showed that the chemical structure differences of CAs had tiny effect on their properties, such as crystallinity, solubility and thermal properties. CA(Homo) and CA(Hete) were all amorphous structure, and they had better solubility in polar organic solvents. The glass transition temperature and thermal stability were similar for these CAs samples. Therefore, CA(Homo) synthesized by homogeneous acetylation in ionic liquids had similar physical properties as those of CA(Hete) prepared by heterogeneous acetylation, but the structure of CAHomo had better uniformity than that of CA(Hete).