Harmful electromagnetic radiation has become a serious problem. High-performance electromagnetic shielding materials play a vital role in controlling or reducing electromagnetic radiation conduction. The high density and poor environmental stability of common metal-based electromagnetic shielding materials severely limit their further development. Ag nanowire (NW) aerogels are feasible lightweight and high-performance electromagnetic shielding materials. Here, we report a hydroxypropyl methylcellulose (HPMC) and Ag NWs composite aerogel that has low density (<77 mg cm–3), high porosity (>95.09%), excellent mechanical properties (tensile strength of 0.27 MPa and compressive stress of 1.3 MPa), and electromagnetic shielding performance of above 89 dB.