Abstract: A series of ZSM-11 was modified by NaOH, HCl acid and Mg loading. The samples were characterized by XRD、FE-SEM、NH3-TPD and BET techniques, respectively. The results show that the modified samples generate a number of mesopores, while aximum crystallinity and micropores are retained. The strong acid centers of the zeolite that facilitate carbon deposition reaction are covered by Mg. Alkylation of benzene with methanol (n（benzene）：n（methanol）=1) was performed over the modified ZSM-11 catalysts under the conditions of 460 ℃, 0.2 MPa and the weight hourly space velocity of 3 h-1. The benzene conversion is 52.60%. The total selectivity of toluene and xylene is 89.91%. The xylene selectivity is 34.08%. The reactivity of modified ZSM-11 is stable in 200 hours alkylation reaction.