The invention discloses large-pore-volume silicon dioxide with a nanoparticle structure and a preparation method thereof. The large-pore-volume silicon dioxide is a product obtained by performing reaction, thermal activation, washing and supersonic air current cutting on alkaline silicate, a sulfuric acid solution and a dispersant serving as raw materials. The silicon dioxide content (dry base) is over 99.0, the BET specific surface area is between 280 m<2>/g and 450 m<2>/g, the void volume is between 2.0 and 3.6, the secondary particle average particle size is between 5 mum and 6 mum, and the primary particle size is between 10 nanometers and 15 nanometers. The average particle size, pore volume and specific surface area of a product produced with the preparation method are controllable;and large-pore-volume silicon dioxide products with different performances can be prepared according to different uses.