Silica composites decorated with metal oxide nanoparticles are prepared based on successive spontaneous reactions. This method does not require any additional acid or base catalyst, thus offers an opportunity to introduce pH-sensitive metal carboxylate groups to silica matrix. Furthermore, the covalent bond of metal carboxylate groups to silica allows the formation of ultrafine and well-dispersed metal oxide nanoparticles in the entire SiO2 matrix.