Uniform core–shell structured Ag@C nanocables (Ag@C-NC) with high aspect ratio (>600) were synthesized by a one-step hydrothermal method, and their PVDF nanocomposites were prepared by a solution casting method. The crystallization properties, thermal stability and dielectric properties of the resulting Ag@C-NC/PVDF nanocomposites were fully investigated. Because of the presence of the carbonaceous shell, the Ag@C-NC exhibits strong interfacial adhesion with the PVDF matrix, leading to a low percolation threshold and low dielectric loss of the resulting nanocomposites. Near the percolation threshold (f_c < 5.49 vol%), high dielectric constant and low dielectric loss were simultaneously achieved in the Ag@C-NC/PVDF nanocomposites. For instance, at 1 kHz, the nanocomposites with 6.45 vol% loading of Ag@C-NC possess a dielectric constant of 295 and a dielectric loss of 0.083. More importantly, the dielectric properties of the resulting Ag@C-NC/PVDF nanocomposites exhibit weak frequency dependence and miniscale temperature dependence.