The invention provides a preparation method of electromagnetic composite hollow microspheres, relates to a preparation method of a composite hollow material and aims to solve the problems of poor 
conductivity, 
high density and high falling possibility of magnetic particles of the existing composite hollow material. The preparation method comprises the following steps: 1, preparing 
polystyrene microspheres; 2, dispersing the 
polystyrene microspheres in concentrated 
sulfuric acid, and sulfonating; 3, preparing a magnetic Fe3O4 nano 
particle suspension; 4, adding the sulfonic-group-containing SPS microspheres and the Fe3O4 nano 
particle suspension into a water solution; 5, adding 
ethanol and 
ammonia water, and dropwisely adding ethyl 
orthosilicate; 6, adding into a PVP-containing 
ethanol solution, and stirring; and 7, mixing an 
aniline solution with the PVP modified magnetic microspheres, dropwisely adding 
ammonium persulfate, 
drying, adding N,N-
dimethylformamide, and soaking. For the prepared hollow microspheres, the 
conductivity is 0.01-1.0 S / cm, the density is low, and the magnetic particles are less prone to fall; and the hollow microspheres are mainly used in the fields of light-weight electromagnetic materials, photonic crystals, wave-absorbing materials and the like.