Abstract: Water produced in the synthesis of ethyl acetate from acetic acid and ethanol can combine with the solid acid catalyst, which results in the loss of active components and reduction of the catalytic activity. Zirconium sulfate (ZS) is a kind of solid acid catalyst with excellent esterification catalytic activity and selectivity. In order to improve the stability of ZS, ZS-AC was prepared by loading ZS over the surface of coconut shell-based activated carbon (AC), and then ZS-AC was modified with silane groups to prepare the hydrophobic solid acid catalyst ZS-AC-C_n, where n was the alkyl chain carbon atom numbers. The Fourier transform infrared (FT-IR) spectra revealed that the solid acid catalysts were successfully grafted with silane group, and the alkyl chain length had a great influence on the hydrophobicity of the catalyst. The liquid-solid contact angles increased in the following order:ZS-AC (40.5°) < ZS-AC-C₄ (94.7°) < ZS-AC-C₇(121.2°) < ZS-AC-C₈ (136°). The reactivity and reusability of these four types of catalysts were investigated at a reaction temperature of 105℃. The results showed that the catalytic activity increased with the increasing of the alkyl chain length, and the catalyst treated with C₇H₁₆O₂Si had the highest activity and stability. Thermogravimetric analysis(TG) showed that the hydrophobic catalyst had a better thermal stability compared to the hydrophilic catalyst. When the molar ratio of acetic acid to alcohol was 4:1, the mass ratio of catalyst to alcohol was 12%, and the reaction time was 4.5 h, the maximum conversion of ethanol reached 98.8% and the yield of ethyl acetate reached 97.2%. At this point, the esterification reaction approached the chemical equilibrium. Moreover, the hydrophobic catalyst was stable in the presence of water which showed the conversion of ethanol was about 92% after repeated use for 4 times.