The invention discloses a fluorine manganate red fluorescent material and a preparation method thereof. The chemical formula of the material is A2Mn1-xF6:xCn+ or BMn1-xF6:xCn+. The preparation methodcomprises the following steps: S1, weighing a K2MnF6 precursor according to a stoichiometric ratio, dissolving the precursor in an HF aqueous solution to prepare a first solution; S2, dissolving oxides of C and fluoride powder into the HF aqueous solution according to a stoichiometric ratio so as to prepare a second solution; S3, dissolving at least one of fluorides and bifluorides of A or B intothe HF aqueous solution according to a stoichiometric ratio so as to prepare a third solution; and S4, uniformly stirring and mixing the first solution and the second solution, slowly adding the thirdsolution, stirring and reacting for a period of time until a yellow precipitate is produced, aging, centrifuging or filtering, washing and drying, thereby obtaining the novel self-luminous fluorine manganate red fluorescent material. The preparation method is simple in operation and applicable to large-scale production.