The invention provides SiO2-WO3 composite aerogel and a preparation method thereof. The specific surface area of the SiO2-WO3 composite aerogel is 329 to 720m<2>/g, the pore volume is 0.6 to 1.8 cm<3>/g, the BJH most probable aperture is 4 to 10 nm and the average aperture is 4 to 9 nm. The preparation method mainly comprises: firstly, synthesizing SiO2-WO3 sol-gel by using sodium tungstate and industrial sodium silicate as raw materials; secondly, modifying a gel block by using modifying solution consisting organic silazane, organic siloxane and an alkane reagent; and finally, replacing porewater. The aerogel product has the characteristics of high specific surface area and high pore volume, the preparation method adopts cheap and readily available sodium tungstate and industrial sodiumsilicate raw materials and therefore can reduce production cost, and a normal pressure drying process is convenient and easy to implement and is suitable for industrial production and use.