H-MCM-22 zeolites with different Si/Al ratios were hydrothermally synthesized, also the parent sample was dealuminated by ammonium hexafluorosilicate (AHFS). Then all of the samples were characterized and evaluated for the methanol-to-olefin (MTO) conversion. The correlation of structural and acidic properties of H-MCM-22 with catalytic performance was investigated. The H-MCM-22 (Si/Al= 35.1) exhibits best catalytic stability in all the samples because of its suitable acid site amount and distribution. As for the H-MCM-22 (Si/Al =35.1) after dealumination by AHFS, most of the extra-framework Al species were selectively removed, the selectivity of light olefin was enhanced further and the coke deposition seems to be inhibited. (C) 2015 Elsevier B.V. All rights reserved.