A series of fluorine-modified Mg-Al mixed oxides were synthesized by thermal decomposition of the fluorine-containing Mg-Al hydrotalcites and then were characterized by ICP, TGA, XRD, FTIR, CO2-TPD and N-2 adsorption/desorption technique. The results revealed that the mesoporous structure was formed during calcination and that fluorine was successfully introduced into the Mg-Al mixed oxides via the phase of MgF2. Simultaneously, such fluorine-modified Mg-Al mixed oxides were effective catalysts for the O-methylation of phenol with dimethyl carbonate (DMC), and their catalytic performance was found to be closely correlated with their basicity. With the optimal catalyst composition, the highest yield of anisole reached 99.3%, with a DMC/phenol molar ratio of 2 at 473 K. (c) 2007 Elsevier B.V. All rights reserved.