The invention provides a preparation method of a carbonyl iron@silicondioxide@ polypyrrole ternary composite wave-absorbing material. The preparation method comprises the following steps: hydrolyzing tetraethoxysilane on the surface of CIP with a sol-gel method to generate a CIP@SiO2 binary wave-absorbing material; generating PPy on the surface of the CIP@SiO2 binary wave-absorbing material to obtain a CIP@SiO2@PPy composite wave-absorbing material through in-situ polymerization. In the prepared composite wave-absorbing material, a dielectric material is introduced on the basis of magnetic loss, so that the impedance matching characteristic of the material is improved, and the wave-absorbing performance of the material is enhanced.