The invention discloses a sodium super ionic conductor-inlaid and coated positive electrode material for a sodium-ion battery and a synthesis method of the positive electrode material. A sodium residue on the surface of the positive electrode material for the sodium-ion battery is taken as a raw material, and the sodium super ionic conductor-inlaid and coated positive electrode material is synthesized in situ through a solvothermal (hydrothermal)-heat treatment technology, wherein the positive electrode material for the sodium-ion battery is NaxMO2 (x is smaller than or equal to 1 and greater than or equal to 0.67, and M is one or more of transition metals of Ni, Co, Mn, Al, Cr, Fe, Mg, V, Zn, Cu and the like); and a super ionic conductor is NayM2(X)3 (y is smaller than 1.5 and greater than 0.3, M is the metal and X is one of polyanions SiO4<4->, PO4<3->, SO4<2->, MoO4<2-> and the like). The sodium residue on the NaxMO2 interface is directly taken as the raw material of the sodium super ionic conductor, so that the positive electrode material disclosed by the invention has the characteristics of in-situ growth and simplicity in process, the storage property of the obtained positive electrode material for the sodium-ion battery is obviously improved, and the positive electrode material is excellent in electrochemical properties and can be used for a power battery and an energy storage battery.