In　this　paper,　TiO2-SiO2　composites　with　different　SiO2　content　s　were　prepared　by　coprecipitation　method　using　rice　husk　ash　as　raw　material.　The　effects　of　the　concentration　of　alkaline　leaching　solution　and　reaction　temperature　on　the　extraction　rate　of　SiO2　from　rice　husk　ash　were　investigated.　The　optimum　formation　conditions　of　TiO2-SiO2　composites　were　explored,　and　the　microstructure　and　properties　of　the　composites　were　analyzed.　The　experiment　al　results　showed　that　the　extract　ion　rat　e　of　SiO2　from　rice　husk　ash　reaches　the　maximum　when　the　concentration　of　alkaline　leaching　solution　is　1.5　mol/L　and　the　reaction　temperature　is　90°C.　When　the　pH　value　is　7,　the　TiO2-SiO2　composites　can　achieve　the　optimum　formation　condition.　TiO2-SiO2　composites　are　composed　of　approximately　spherical　particles　with　obvious　pore　structure　of　the　surface　and　piling　up　in　fluffy　state.　The　Si　atoms　enter　the　crystal　structure　of　TiO2　with　Ti-O-Si　bonds　connected　to　Ti　atoms,　which　inhibits　the　growth　of　TiO2　grains　and　leads　to　the　increase　of　the　transition　temperature　of　TiO2　from　anatase　to　rutile.　©　The　Authors,　published　by　EDP　Sciences,　2018.