The nanosized CeO2-TiO2-SiO2 mixed oxide powder has been synthesized by the gel combustion method using polyvinyl alcohol (PVA) as polymer basic and mixture of cerium (IV) nitrate, titanium (III) chloride and silane. Effects of preparative parameters on the phase formation of CeO2-TiO2-SiO2 such as Ce-Ti-Si molar ratio, calcination temperature have been investigated and discussed. The results showed that, for the optimized procedure with pH = 1, temperature of gel formation of 80°C, molar ratio of metal over polyvinyl alcohol of 1/3, molar ratio of Ce-Ti-Si of 1-1-8. The CeO2-TiO2-SiO2 mixed oxides were obtained with the averge grain size of nanopowders up to 97 nm after calcined at 850°C for 2 hours.