3D copper nanowires-thermally annealed graphene aerogel (CuNWs-TAGA) framework is firstly prepared by freeze-drying followed by thermal annealing from CuNWs, graphene oxide (GO) and L-ascorbic acid. Epoxy resin is then poured back into the above 3D CuNWs-TAGA framework to fabricate the CuNWs-TAGA/epoxy nanocomposites. CuNWs with average diameter of about 120?nm and length of approximate 10?μm are successfully prepared. When the mass fraction of CuNWs-TAGA is 7.2 wt% (6.0–1.2 wt% CuNWs-TAGA), the thermal conductivity coefficient (λ) value of the CuNWs-TAGA/epoxy nanocomposites reaches the maximum of 0.51 W/mK. Meantime, the CuNWs-TAGA/epoxy nanocomposites exhibit the maximum electromagnetic interference shielding effectiveness (EMI SE) value of 47?dB and electrical conductivity (σ) of 120.8 S/m, ascribed to perfect 3D CuNWs-TAGA conductive network structures. Meanwhile, the corresponding elasticity modulus, hardness, glass transition temperature (T_g) and heat-resistance index (T_HRI) of the CuNWs-TAGA/epoxy nanocomposites increase to 4.69? GPa, 0.33? GPa, 126.3°C and 181.7°C, respectively.