Mesoporous materials functionalized with STA(Silicotungstic acid) have been proved to be efficient catalysts for esterification reactions. In the investigation, impregnation method was applied for the synthesis of STA/MCM-41 catalysts. MCM-41 and STA(Silicotungstic acid) were used to silica source and active material respectively. The active material was loaded by dry-impregnation method after silica source. Molar ratios of catalysts were determined by 1.25, 2.5 and 5% (W/Si). Actually, this molar ratio values are very low for the impregnation method. But catalysts were successfully synthesized by applying impregnation method. And catalytic activities of STA/MCM-41 catalysts were investigated with an ethyl acetate reaction. On the other hand, the second reaction of STA/MCM-41(2.5%) catalyst was carried out in the presence of under identical conditions after the first reaction. Before and after reactions, the physical properties of the catalysts were determined by XRD, DRIFT, BET, SEM and Mapping analysis methods.