The invention relates to a preparation method of a composite material, in particular to a preparation method of a Ti5Si3/TiAl based composite material, which solves the problem that the existing preparation method of the Ti5Si3/TiAl based composite material has high cost. The method comprises the following steps: putting TiH2 powder in a graphite mould to obtain a TiH2 preform; arranging an Al-Si alloy scrap material on the preform; and arranging the graphite mould into a vacuum hotpressing sintering furnace for vacuum pressurization hot junction to obtain the Ti5Si3/TiAl based composite material. The hardness of the composite material prepared by the invention is 4GPa-6GPa, the tensile strength at 700 DEG C is 600MPa-800MPa, and the preparation cost is low. The composite material can be used as a novel high-temperature structural material of aeronautic and aerospace aircrafts.