There are many kinds of nanocapsules. Shell materials include graphite, CNx, boron nitride and disulfide (MX2, M = W, Mo, Nb, Ta; X = S, Se, Te) and other layered substances, polymers and phosphates, SiO2, semiconductors, oxides, etc. Core materials include various metals, nonmetallic elements and compounds. As a mesoscopic system between macroscopic objects and atoms, nanocapsules are similar to macroscopic objects and atoms, and also have many unique properties and uses. It combines the characteristics of core-shell structure with the influence of nano-system size change. The shell of nanocapsules has many functions, such as: protecting the inner core from environmental damage; Increase the stability of nanoclusters to avoid their growth; Promote the dispersion of nanoparticles in different media; Increase the activity of substances; Change the optical, electrical and magnetic properties of the core.