La3+-SiO2　doped　nano-TiO2　was　synthesized　via　hydrothermal　process　with　tri-block　non-ion　surfactant　P123　as　template.　The　structures　and　optical　properties　of　the　synthesized　samples　were　characterized　via　XRD,　DRS,　FT-IR　etc.　The　results　showed　that　the　grain　growth　of　TiO2　was　hindered　by　La　and　SiO2　doping.　The　formation　of　Ti-0-Si　bond　and　Ti-O-La　bond　suppressed　the　formation　of　the　rutile　phase　and　the　growth　of　titanium　dioxide　crystals,　and　improved　thermal　stability　of　TiO2,　therefore　obtained　high　purity　of　anatase　phased　nano-TiO2.　The　spectra　response　range　of　TiO2　was　extended　to　visible　light　substantially　by　La-SiO2　doping,　then　photocatalytic　performance　was　improved　effectively.　Compared　with　pure　nano-TiO2,　the　performance　of　La3+-SiO2　doped　nano-TiO2　which　photocatalyticly　degraded　methyl　orange　was　increased　significantly.