The invention discloses a self-locking coated lithium titanate material and a preparation method thereof. The method comprises the following steps of 1) uniformly mixing a titanium source and a lithium source or uniformly mixing the titanium source, the lithium source and a dispersing medium, and performing spray drying, wherein an excessive amount of lithium element is used; 2) performing primary roasting in an atmosphere containing a nitrogen gas to obtain a material I, and performing ball-milling to obtain a material II; and 3) uniformly mixing and drying the material II and a carbon source, performing secondary roasting in an inert atmosphere to obtain the self-locking coated lithium titanate material. The material is of a three-layer core-shell structure, wherein the core is lithium titanate, a skin layer is a carbon layer, an intermediate layer is a Li-N layer, and a C-N bond is arranged between the carbon layer and the Li-N layer. By the method, the electron conductivity of the material is improved, the problem that a lithium titanate battery is easy to generate bubbles is solved, the adhesive force between a coating layer and a substrate material is substantially improved, so that the material has better rate performance, low-temperature performance and cycle stability.