A facile one-pot method was used to prepare C18-bonded ethyl-bridged organic-inorganic hybrid silica via the co-hydrolysis and condensation of 1,2-bis(triethoxysilyl)ethane (BTESE) and octadecyltriethoxysilane (ODTES) under basic condition. The pore structure, chemical composition and liquid chromatographic performance of the obtained materials were investigated. The sample MSS-0.08, prepared with an ODTES/BTESE mole ratio of 0.08, exhibits a desirable mesoporous structure with a surface area of 352.82 m2 g−1, a pore volume of 0.21 cm3 g−1 and an average pore size of 3.72 nm and shows a hydrophobic property with a water contact angle of 139.8° ± 0.1°. When used as stationary phase for high performance liquid chromatography (HPLC), MSS-0.08 realizes a baseline separation for a mixture of uracil, pyridine, phenol, 1-naphthylamine and naphthalene and exhibits a high degree of resistance to alkali at elevated temperature.