The invention provides a preparation method of a low-cost lithium titanate material. The preparation method comprises the following steps of (1) allowing metatitanic acid to react with hydrogen peroxide, adding an appropriate amount of ammonia water to form a stable titanium peroxide complex solution; and (2) weighting a lithium source according to a proportion, adding the lithium source into thetitanium peroxide complex solution prepared in the step (1), adding a dispersing agent, stirring to form a uniform solution, and drying and roasting to prepare the lithium titanate material. The low-cost metatitanic acid (the cost is about one third of titanium dioxide) is a titanium source, the cost is reduced, the appropriate amount of hydrogen peroxide and the ammonia water to prepare the stable titanium peroxide complex compound, the titanium peroxide complex compound more fully reacts with a lithium salt, the prepared lithium titanate material is excellent in performance, the half-batteryinitial capacity is 174mAh/g, and the initial charge-discharge efficiency is larger than 95%.