Undoped CNTs and N-CNTs were synthesized by chemical vapor deposition using Fe catalyst, and then melt-mixed in an APAM mixer with polyvinylidene fluoride (PVDF) to prepare the nanocomposites. The morphology, crystallinity, aspect ratio, nitrogen content, and nitrogen bonding type of CNTs, and the broadband dielectric properties of Undoped CNT/PVDF and N-CNT/PVDF nanocomposites were analyzed. The results showed that while Undoped CNTs presented a crystalline structure with open channels, doping with nitrogen resulted in CNTs with a bamboo-like configuration, inferior crystallinity, smaller length, and larger diameter. The N-CNT/PVDF nanocomposites, thus, had a higher percolation threshold (~3.5wt.%) compared to that of the Undoped CNT/PVDF nanocomposites (~0.5wt.%). Comparison of the broadband dielectric properties of the generated nanocomposites revealed that nitrogen doping improved the dielectric properties in the insulative region. This was ascribed to the role of nitrogen atoms and their sequent defects in the nanotubes, which acted as scattering centers and provided additional polarization sites. For instance, 1.0wt.% N-CNT/PVDF nanocomposites exhibited a real permittivity of ε'=22 and a dissipation factor of tan δ=0.03 at 1kHz, a combination superior to that of 0.5wt.% Undoped CNT/PVDF nanocomposite with ε'=11.2 and tan δ=3.8, and 1.0wt.% Undoped CNT/PVDF nanocomposites with ε'=40 and tan δ=1.4×105.