The hydrophobic silica membrane was prepared on the porous alumina support with γ-alumina interlayer by sol-gel method. The hydrophobilizing of silica membrane was carried out using phenyltriethoxysilane (PhTES). In addition, cetyl trimethyl ammonium bromide was used to control the pore size by molecular template, and to enhance the flux through the membrane. The structure of the hydrophobic silica membrane characterized by FT-IR and N2 adsorption-desorption isotherms using the powder which is dried at 453 K. The FT-IR results of hydrophobic silica membrane, which is prepared using PhTES and tetraethoxysilane (TEOS), showed the reduction of the presence for Si-OH groups, and indicated the presence of phenyl group compare with silica membrane which is prepared using TEOS only. These membranes were used for separation of methyl ethyl ketone (MEK) and ethyl acetate (EA) in aqueous solutions. The permeation flux and separation factor of EA (5 wt%) / water using the hydrophobic silica membrane prepared with CTAB indicated 2.07 kg m-2 h-1 and 371, respectively. This value is higher than that of the membrane prepared without CTAB. The flux for EA/water and MEK/water mixtures increased with increasing of temperature. On the other hand, the separation factor is maintained virtually constant, regardless of the increasing of temperature. This is considered that the blocking effect, which is occurred by the selective adsorption between phenyl groups and organic molecules, is maintained without relation to the certain level of temperature due to the strong interaction between phenyl groups and organic molecules.