Abstract: Mesoporous silica host was obtained by using sol-gel technique, leading to a formation of Ni/SiO₂ nanocomposite through the immersion of nickel nitrate solution and hydrogen reduction treatment. The optical properties of the silica mesoporous composites were investigated. With increasing the composition and reducing the treatment temperature, the nanoparticles grow and the optical absorption edges red-shift due to the surface effect of the nano-particles. The optical properties are related to the interactions between the particles and the mesoporous host and the electron transferring. The optical absorption of the mesoporous composites contained the nanosized metal particles well correlated to the absorption mode of the indirect band transistor. The optical absorption increases with the loading of rare earth Ce. After being reduced at H₂ atmosphere, the absorption edge red-shifts largely with the increase of the amount of rare earth Ce.