A borosilicate glass powder is used as a raw material, carbon black is used as a foaming agent, and ferric oxide is used as an additive to prepare a foam glass substrate. Conductive polyaniline/foam glass compo-sites were prepared by in-situ polymerization and emulsion polymerization using aniline (An) as mono-mer and ammonium persulfate (APS) as initiator. The morphology and structure of foam glass and com-posites were characterized by FTIR, XRD and SEM. The electromagnetic parameters of the materials were measured by vector grid analyzer, and the reflection loss of the materials was simulated. The results show that when the carbon black content is 0.03wt% and the molar ratio of carbon black to ferric oxide is 3:2, the prepared foam glass has a pore size of 1 mm to 1.2 mm and a compressive strength of 1.7 MPa to 2.45 MPa. The results of electromagnetic parameter test and reflection loss show that the composite has the best absorbing property when the concentration of polyaniline is 0.1mol/l. The minimum reflection loss of the composite obtained by in-situ polymerization was -12.56 dB, and the effective bandwidth was 2 GHz (8.2 GHz - 10.2 GHz). The minimum reflection loss of emulsion polymerization is -13.38dB, and the effective bandwidth is 2.2GHz (8.2GHz-10.4GHz).