The invention discloses a composite nano silicon dioxide / quartz stone plate product and a preparation method thereof. The composite nano silicon dioxide / quartz stone plate product is prepared from the following components and raw materials in parts by weight: quartz stone sand, pigment, a silane coupling agent, nano silicon dioxide, unsaturated polyester resin, a curing agent and a certain amountof accelerant by the steps of mixing, adding to a mold, carrying out vibration compaction, curing, determining thickness, grinding and polishing and carrying out other working procedures. The invention also discloses a preparation process of the composite nano silicon dioxide / quartz stone plate product. According to the invention, the prepared composite nano silicon dioxide / quartz stone plate is a composite quartz stone plate product which is a large network structure formed by tight embedding and chemical bond cross-linking of all the components; and the prepared composite quartz stone plateproduct has the advantages of high silicon dioxide content, high strength and hardness, ultraviolet aging and thermal aging resistance, high fire retardancy and high heat insulating property, compactand glabrous surface and durability. The use range of the quartz stone plate is enlarged.