Abstract: A preparation method of a nanosheet nitrogen-containing porous carbon material includes steps of: dissolving alkali and water-soluble amine-containing compound in water, forming an aqueous solution; adding cellulose or a derivative thereof into the aqueous solution; after mixing and drying, obtaining a crystal composite of the alkali and the water-soluble amine-containing compound, wrapped by the cellulose or the derivative thereof; carbonizing the crystal composite under nitrogen gas flow; washing a crabonized product; and obtaining the nanosheet nitrogen-containing porous carbon material. Through changing a proportion among the alkali, the water-soluble amine-containing compound and the cellulose or the derivative thereof, a specific surface area, pore structure, nitrogen content and thickness of the nanosheet nitrogen-containing porous carbon material are adjusted.