A composite material of sandwich structure integrating loading, heat insulation and ablation and the manufacturing method are characterized in that an integrated pre-forming body is acquired by puncture and suture of the reinforcing material of a bearing layer, the reinforcing material of an ablating cover, and a heating insulation layer positioned between the two layers; an epoxy resin system and a phenolic resin system are injected simultaneously into a vacuum-pumped mould, in which the integrated forming body is pre-placed, by two sets of RTM injection systems respectively, then, the reinforcing materials of the bearing layer and the ablating layer are soaked by epoxy resin and phenolic resin respectively; and the composite material of sandwich structure integrating loading, heat insulation and ablation can be obtained by solidified molding after mould filling. The invention has the advantages that the composite material of sandwich structure integrating loading, heat insulation and ablation is put forward and can be integrally formed by one-time operation, the function of the interlayer between every layer of the composite material is enhanced greatly, the integrality is good; the stratifying and peeling of the composite can be reduced effectively, and the products have good designable property and can be widely applied to the structural parts of aerospace which need heating insulation and thermal protection.