Nanomaterials usually have special mechanical, optical, magnetic, electrical, catalytic and other characteristics, so they are significantly valuable for applications. For example, ZnO and ZnMgO nanoparticles can be used in charge transport layer of QLED; Fe3O4 magnetic nanoparticles can be used for biological separation, magnetic hyperthermia, targeted drug delivery and magnetic resonance imaging; nano-Ag can be used for antibiosis, catalysis, conductive ink, etc. Additionally, if prepared as nanoparticles, the catalytic effect of metallic catalysts such as Fe, Co, Ni, Pd and Pt can be considerably improved. Specifically, Ni powder in sized 30 nm can make the rate of organic chemical hydrogenation or dehydrogenation reaction increased by 15 times. Further, the sintering temperature of Si3N4 is conventionally above 2000° C., while the sintering temperature of nano-Si3N4 can decrease to 1500-1600° C., and the sintered products can obtain a hardness and strength higher than ordinary ceramics by 4 to 5 times.