The invention discloses a mono-dispersed nitrogen doped hollow carbon nano polyhedron and a preparation method thereof. The mono-dispersed nitrogen doped hollow carbon nano polyhedron takes a ZnO nano-sphere as a template and a Zn source and 2-methylimidazole as organic ligands to synthesize a core-shell-structure ZnO@ZIF-8 nano mono-crystal composite material; the core-shell-structure ZnO@ZIF-8 nano mono-crystal composite material is put into a high-temperature furnace and is calcined in an inert gas atmosphere for 2h to 4h, wherein the calcination temperature is 800 DEG C to 900 DEG C; after calcination, a carbon nano material with a hollow structure is directly obtained. A preparation process disclosed by the invention is simple, and a template removing process is not adopted. The carbon nano material with the hollow structure, which is prepared by the method disclosed by the invention, has a uniform polyhedron shape, a high specific surface area and high nitrogen content, and has a great application potential in the fields including electrochemical energy storage, catalysis, fuel batteries and the like.