The homogeneous esterification of cellulose was conducted without any catalysts under mild conditions in an ionic liquid，1-butyl-3-methylimidazolium chloride（［Bmim］Cl），using chloroacetyl chloride as esterifying agent. The influence of reaction temperature，reaction time and the amount of esterifying agent on degree of esterification were investigated. The modified cellulose was characterized by IR and NMR，and the solubility of the product in solutions was also investigated. It was found that the DS of the modified cellulose could be 1.36 under the conditions as follows：the molar ratio of cellulose anhydroglucose unit to chloroacetyl chloride was 1∶3，the reaction time was 2 h，and the reaction could be carried out at room temperature. Moreover，the modified cellulose could easily solute in some organic solutions，such as acetone，dimethyl sulfoxide and tetrahydrofuran..