As a promising alternative anode material, silicon (Si) presents a larger capacity than the commercial anode to achieve large capacity lithium-ion batteries. However, the application of pure Si as anode is hampered by limitations such as volume expansion, low conductivity and unstable solid electrolyte interphase. To break through these limitations, the core-shell Si@Li4Ti5O12 nanocomposite, which was prepared via in-situ self-assembly reaction and decompressive boiling fast concentration method, was proposed in this work. This anode combines the advantages of nano-sized Si particle and pure Li4Ti5O12 (LTO) coating layer, improving the performance of the lithium-ion batteries. The Si@Li4Ti5O12 anode displays a high initial discharge/charge specific capacity of 1756/1383 mAh g−1 at 500 mA g−1 (representing high initial coulombic efficiency of 78.8%), a large rate capability (specific capacity of 620 mAh g−1 at 4000 mA g−1), an outstanding cycling stability (reversible specific capacity of 883 mAh g−1 after 150 cycles) and a low volume expansion rate (only 3.3% after 150 cycles). Moreover, the synthesis process shows the merits of efficiency, simplicity, and economy, providing a reliable method to fabricate large capacity Si@Li4Ti5O12 nanocomposite anode materials for practical lithium-ion batteries.