A lithium titanate/titanium niobate core-shell composite material includes a core which comprises lithium titanate; and a shell which is cladded over the core and comprises titanium niobate. A preparation method of lithium titanate/titanium niobate core-shell composite material includes (A) mixing lithium titanate powder and titanium niobate powder; and (B) granulating the mixture produced by step (A) through a spray granulation process to obtain a lithium titanate/titanium niobate composite material with titanium niobate cladding over lithium titanate. The lithium titanate/titanium niobate core-shell composite material and the preparation method thereof can be applied to a battery.