The invention discloses a cobalt ferrite-nitrogen doped carbon composite negative electrode material for dynamic lithium battery and a preparation method thereof. The negative electrode material is composed of cobalt ferrite nano particles which are coated by nitrogen-doped carbon. The particle size of the negative electrode material is 20 to 50 nm, the thickness of the nitrogen-doped carbon is 2.5 to 3.5 nm, the CoFe2O4 content is 65.2 wt%, the FeCo content is 19.7 wt%, the Co content is 4.6 wt%, and the nitrogen doped carbon content is 10.54 wt%. The preparation method comprises the following steps: placing cobalt ferrite powder into a high pressure reactor, dropwise adding an organic carbon source to soak the powder; sealing the reactor, placing the sealed reactor into a resistor furnace, heating to a temperature of 450 to 600 DEG C, maintaining the temperature for 4 to 8 hours; and washing the reaction products after the furnace cools down so as to obtain the composite negative electrode material. Because the nitrogen doped carbon layer has an effective buffering function and an electro-conductive property, the obtained cobalt ferrite-nitrogen doped carbon composite negative electrode material has better electrode integrity and a smoother electrode kinetic property than those of the pure cobalt ferrite negative electrode, and the provided material has excellent cycling stability and capacity recovering performance. Moreover, the preparation method of the composite material is simple and is easy for massive production.