The invention discloses a charcoal-coated metal fluoride nano material with a core-shell structure, a preparation method and application of the nano material in the field of lithium ion battery positive electrodes. The nano material is of a core-shell structure; the shell layer is charcoal; the core layer is metal fluoride; the nano material has high specific capacity and good cyclic stability by being taken as the positive electrode material of a lithium ion battery. The nano material with the core-shell structure can be prepared through the processes of mixing, pyrolysis and solvent washing of a raw material metal compound and a fluorine-containing compound, has the characteristics of abundant source of raw material, simple process, low material preparation cost, high purity, wide metal choice range and the like, and facilitates large-scale production.