The invention discloses a preparation method of a sodium ion battery high capacity graphite negative electrode material. The method comprises the steps of: (1) adding a certain amount of graphite slowly into sulfuric acid with a concentration of 20-80%, then adding an oxidizing agent and a titanium source in order, carrying out stirring reaction in water bath at a constant temperature of 20-70DEG C for 0.5-4h, then performing washing to a ph of 6.0-7.0, conducting filtering, and then carrying out drying at 80-100DEG C to obtain titanium inserted graphite; and (2) placing the titanium inserted graphite obtained in step (1) in an atmosphere furnace at 500-1000DEG C to carry out high-temperature treatment for 4-10h, thus obtaining the sodium-ion battery high capacity graphite negative electrode material. The method provided by the invention inserts the titanium source to the graphite interlayer to enlarge the interlayer spacing of graphite so as to reserve the contraction and expansion space for intercalation and deintercalation of sodium ions, and at the same time broadens the diffusion channel of sodium ions, thus being conducive to enhancing the specific capacity of graphite and improving its rate performance. At the same time, the titanium oxide generated by the titanium source inserted to the interlayer can greatly increase the embedding capacity of the sodium ions, thereby further increasing the specific capacity.