Fabricating lightweight and mechanically robust carbon aerogel (CA) for high-performance electromagnetic interference (EMI) shielding is vital yet challenging. In this work, the heterostructure CA/SnO 2 nanorods (NRs) composites are proposed by the fabrication of phenolic-derived CA and followed in-situ growth of nano rod-like SnO 2 via ultrasonic cavitation effect. This strategy introduces countless heterogeneous interfaces in the skeleton while maintaining the original porous conductive skeleton of CA, which can synergistically dissipate and absorb electromagnetic waves. The CA/SnO 2 NRs composites exhibit the EMI shielding effectiveness (SE) of 36.6 dB with a density of 0.33 g cm −3 , of which the absorbed SE reaches 32.1 dB. Besides, CA/SnO 2 NRs composites also exhibit prominent mechanical properties, flame retardant properties, and outstanding thermal insulation. Such an especial combination of several exceptional properties capacitates the EMI shielding CA/SnO 2 NRs composites to have broad application prospects in fields of aerospace, military, and intelligent electronics.