A novel route to prepare hydrophobic mesoporous SiO2 films is reported in this paper. A two step process involving tetraethyl orthosilicate (TEOS) as a precursor and cetyltrimethyl ammonium bromide (CTAB) as a template prepared SiO2 sol catalyzed by hydrochloric acid. The films are prepared by dip-coating process. It has been found that the films have low dielectric constant and good mechanical properties. Preliminary results present a very positive prospective for intermetal dielectric applications.