Abstract: The highly ordered mesoporous silica with hexagonal symmetry was synthesized by using an oligomeric surfactant as template under neutral condition. The effect of different molar ratio of surfactant to silicate on the surface structure of the product was studied by small-angle X-ray diffractometry. The results showed that the structure of the resulting product has hexagonal symmetry and the ordering of pore structure increased with the improving of the molar ratio of surfactant to silica. When the molar ratio of surfactant to silica was more than 35, product with high quality could be obtained. The ordering of pore structure was the highest at 1:8 of the ratio of surfactant to silica. Nitrogen adsorption-desorption test indicated that the BET surface and total pore volume of the product increased rapidly with the increase in the molar ratio of surfactant to silica and the type of N₂ adsorption isotherm transformed from Ⅱ to Ⅳ at n(surf):n(Si)=1:35. The molar ratio of surfactant to silica hardly showed effect on the most probable pore size and pore wall thickness which was found to be 3.74~3.76 nm and 0.54~0.69 nm, respectively.