Silicon is considered as one of the most promising lithium anode materials due to its high lithium storage capacity.However, the volume expansion effect and semiconductor properties of silicon hinder its practical application. Two effective strategies exist for mitigating this issue, i.e., reducing the size of silicon to nanoscale; and introducing non-active matrices to improve stability and conductivity. In recent decades, the incorporation of iron silicide (FeSi2) with silicon (Si) has attracted much attention due to its high conductivity, mechanical hardness and environmental friendliness. Unfortunately, the Si/FeSi2 nanocomposites are mainly prepared by high-energy ball milling, which has some drawbacks such as low purity, large particle size, and uncontrollable morphology, making it difficult to achieve the commercial application. Porous silica derived from clay minerals is extensively investigated for the preparation of silicon nanoparticles by magnesiothermic reduction. In addition, porous silica has a large specific surface area, which facilitates the effective dispersion and loading of iron oxides. The reduction of iron oxide and silica dioxide to Fe and Si can be achieved by magnesium. In this paper, a natural montmorillonite (Mnt) with a high content of silica (65%, in mass) was utilized as a raw material. Silicon/iron silicide (Si/FeSi2) nanocomposites were synthesized via modification of Mnt (including acid etching and iron loading) and molten salt-assisted magnesiothermic reduction.