The invention discloses a preparation method of a rare earth-aluminum intermediate alloy ingot suitable for a lithium ion battery. The preparation method of the rare earth-aluminum intermediate alloy ingot suitable for the lithium ion battery comprises the steps that (1) rare earth elements are added into ionic liquid A to be dispersed, and carbon dioxide or ammonia gas is introduced into the ionic liquid A, so that sediment and ionic liquid B are obtained; (2) the sediment and the ionic liquid B are placed into a grinding machine to be ground, so that nano materials with the particle sizes of 1-200 nm are obtained; (3) reduced pressure distillation is conducted on the nano materials, so that nano particles are obtained through extraction; (4) the nano particles are cleaned and heated to be dried; (5) the dried nano particles and aluminum powder are ground, mixed, stirred and crushed into pressed powder; (6) the pressed powder is stirred in an electromagnetic stirring furnace so as to be molten into aluminum-based intermediate alloy; and (7) the aluminum-based intermediate alloy is cast into the rare earth-aluminum intermediate alloy ingot. Correspondingly, the invention further discloses the rare earth-aluminum intermediate alloy ingot prepared through the method. The rare earth-aluminum intermediate alloy ingot is high in strength, heat conductivity and electric conductivity, good in mechanical property and resistant to electrochemical corrosion.