Abstract: Multi-material composite is an effective method to prepare light-weight, broadband and strong absorbing materials. In this paper, polylactic acid (PLA) was used as the matrix material, and FeSiAl, MoS₂ and graphene (GN) were used as fillers. FeSiAl-MoS₂-GN/PLA composites, which were used for fused deposition modeling (FDM), prepared by the two-step process of ball milling and melt extrusion. The phase structure, microscopic morphology and electromagnetic properties of composites were characterized by XRD, Raman spectroscopy, SEM and vector network analyzer, respectively. And the effect of graphene content on the electromagnetic wave absorbing properties of composites was also investigated. The research shows that graphene, FeSiAl and MoS₂ are randomly dispersed in the PLA matrix and form a complex conductive network; Multi-material composites build rich dielectric/magnetic heterointerfaces, which are beneficial to promote interface polarization; The higher the graphene content, the stronger the electromagnetic wave absorbing properties of composites; When the graphene content is 5wt%, the minimum reflection loss is −27.90 dB at a thickness of 1.7 mm, and the effective absorption bandwidth is 4.96 GHz (12.64-17.60 GHz) at a thickness of 1.9 mm. Its excellent absorbing properties are attributed to the perfect impedance matching and the synergy between dielectric and magnetic losses.