Disclosed in the present invention is a preparation method for a fluorine-doped Prussian-blue-type sodium ion battery positive electrode material. The method comprises: preparing a mixed solution of sodium ferrocyanide and sodium fluoride, adding an antioxidant into the mixed solution, adding a transition metal salt solution into the mixed solution at a certain flow rate, adding a sodium chloride solution into the mixed solution after material addition ends and aging same, carrying out a solid-liquid separation on the aged material to obtain a precipitate, and washing and drying the precipitate to obtain a Prussian-blue-type sodium ion battery positive electrode material. The mixed solution in the present invention contains a large amount of fluorine ions, which are complexed with transition metal ions when the transition metal ions are added, so that the precipitation reaction speed is inhibited, crystallization is carried out slowly, and particles with better crystallinity are thus obtained; the metal sodium salt complexed with fluorine also generates a precipitate as the reaction is carried out, and is co-precipitated with ferrocyanide to form a eutectic; and the fluorine ions play the role of supporting the framework of the material.