The invention provides a siliceous composite material, comprising silicon particles and a clad wrapped on the surface of silicon particles, wherein, the clad is conducting polymer. The siliceous composite material provided by the invention takes the conducting polymer as the clad; the polymer does not need to be transformed further into 'hard carbon', and the siliceous composite material is guaranteed to have excellent conductivity; meanwhile, the aggregation between silicon particles can be avoided. When the composite material is taken as negative active material of a lithium iron battery, the lithium iron battery is ensured to have high reversible capacity and good cycle performance. Therefore, the invention can be taken as the negative active material of the lithium iron battery. As the polymer does not need to be transformed further into the 'hard carbon' and the siliceous composite material has good conductivity in the preparation of the siliceous composite material provided by the invention, the manufacturing technique is simplified and the problem of huge energy consumption caused by the high temperature carbonization process in the prior art is solved.