The synthesis of methyl chloroacetate from chloroacetic a cid and meth anol over HZSM 5 and modified HZSM 5(i.e. HZSM 5A and HZSM 5B) catalysts has bee n studied. The reaction conditions have been optimized. Over 95% conversions of chloroacetic acid could be achieved at the optimum reaction conditions. The mod ified catalysts with higher acidity in weak acidic region showed relatively high catalytic activities.