Magnesium thermal reduction of the silica aggregation following with HF etching is used to obtain mesoporous nano-Silicon. The product shows an 1844 mAh g−1 discharge capacity in the first cycle with 400 mA g−1 current density and it still delivers a 1444 mAh g−1 capacity after 100 cycles. Additionally, it presents a good rate capability. The mesoporous morphology and the ultra-fine particle are the reasons of the good electrochemical property.