Abstract: The 3D graphene-multi walled carbon nanotube/thermoplastic polyurethane (GA-MWCNTs/TPU) composites were prepared using 3D graphene-multi walled carbon nanotubes aerogels (GA-MWCNTs) and thermoplastic polyurethane (TPU). GA-MWCNTs was prepared by hydrothermal reduction method for grafting carboxylated multi-walled carbon nanotubes (MWCNTs-COOH) onto graphene oxide (GO) and then freeze-drying. Subsequently, the filling TPU was impregnated the GA-MWCNTs in a vacuum state to obtain the GA-MWCNTs/TPU composite. The chemical structure and microstructure of GA-MWCNTs were characterized by means of FTIR, Raman, XPS, TEM and SEM, then MWCNTs-COOH mass fraction effect on the GA-MWCNTs/TPU composite performance was analyzed by means of TGA-DSC, resistance measuring instrument and mechanical testing machine. The results demonstrate that MWCNTs-COOH can cross-linking and support the GO inter-lamellar structures, forming a honeycomb 3D network structure with a pore size of about 1.2 mm. When the mass fraction of MWCNTs-COOH (using 120 mg GO as reference) is 10wt%, the electrical conductivity, thermal stability and mechanical properties of GA-MWCNTs/TPU composite are greatly improved. Compared with the GA/TPU, the volume resistivity of GA-MWCNTs/TPU composite reduces by 63.0%, thermal decomposition temperature increases by 7℃, and the stress at 30% strain increases by 8.2%.