The invention provides CaCO.sub.3/SiO.sub.2.nH.sub.2O nanocomposite particles and method of producing the same. A template nucleus is used calcium carbonate and the surface of nucleus is encapsulated by a SiO.sub.2.nH.sub.2O nanolayer. The invention also provides a CaCO.sub.3/SiO.sub.2.nH.sub.2O nanocomposite particles having hollow structure, in which n=0-2. The nanocomposite particles according to the invention have a number of uses.