Abstract: Titania-silica (TiO<SUB>2</SUB>-SiO<SUB>2</SUB>) composite aerogel was prepared by sol-gel method and supercritical drying technique,taking ethanol as solvent.Through comparing the photocatalytic activity of aerogels prepared with different components,calcination temperatures,and calcination time,the optimum technological conditions were obtained,which were as follows: mass ratio of TiO<SUB>2</SUB> to SiO<SUB>2</SUB> was 1∶1,calcination for 2 h at 600 ℃ after supercritical drying.Final composite aerogel product has perfect network and uniform nano-mesoporous structure;its specific surface area reached 355.6 m<SUP>2</SUP>/g,pore volume was 0.32 mL/g,the most probable pore radius was 0.82 nm,and mean pore radius was 2.52 nm;TiO<SUB>2</SUB> was anatase type structure and SiO<SUB>2</SUB> was amorphous.