The invention discloses a preparation method for preparing an Al/SiC-C-SiC composite material through vacuum air pressure infiltration. The Al/SiC-C-SiC composite material comprises, by volume, the following components: 30% of aluminium alloy, 10% of slice layer graphite and 60% of SiC. The preparation method for preparing the Al/SiC-C-SiC composite material through vacuum air pressure infiltration comprises the steps that "sandwich"-structured SiC-C-SiC is prepared in advance; a multilayer preform accounts for 70% of the composite material; then the "sandwich"-structured SiC-C-SiC and the multilayer preform are put into a mold, and liquid aluminum melted beforehand is pressed into the "sandwich"-structured SiC-C-SiC and the multilayer preform through pressure; and at last, under certain pressure difference, cooling and solidification are conducted, and the "sandwich"-structured Al/SiC-C-SiC composite material is prepared. By means of the manufacturing technology adopted in the preparation method, deformation of the composite material is minute; heat conduction capacity is high; and stability of machining size can be guaranteed. The preparation method for preparing the Al/SiC-C-SiCcomposite material through vacuum air pressure infiltration has the advantages that the manufacturing process is simple; operation is easy; and mass production can be achieved.