Core-shell structure nanocomposite, namely a layer or multilayer of inorganic or organic materials are coated on the outer surface of inorganic or organic particles with a certain interaction force to form a composite nanomaterial with core-shell structure. Core-shell nanocomposites can improve the deficiencies of the outer core and inner shell and improve the optical, electrical, magnetic, catalytic and other properties of the material. According to the difference of core and shell layer, it can be divided into various categories, and there are various preparation methods. The interaction between core and shell makes core-shell nanocomposites exhibit various excellent functional properties, which are widely used in many fields. In catalytic applications, core-shell nanocomposites not only exhibit good chemical resistance, but also effectively reduce the agglomeration and sintering of nanoparticles. We provide the classification, preparation methods and applications of core-shell nanocomposites in the field of catalysis, briefly expound their formation mechanism, and prospect their future development directions.