The electrical and dynamic mechanical behavior of barium titanate (BaTiO 3 )/vaporgrown carbon fiber (VGCF)/Low Density Polyethylene (LDPE) composites has been studied. The measurement of electrical conductivity exhibits a lower percolation threshold and a more distinct two-stage percolation region, especially with a wide plateau between the two stages, for BaTiO 3 /VGCF /LDPE composites compared to the two-component system of VGCF /LDPE. This can be attributed to increase of the effective concentration of VGCF and the obstruction of BaTiO 3 particles on VGCF networks. The dynamic mechanical spectra of BaTiO 3 / VGCF /LDPE composites present a distinctive α relaxation region with its peak value nearly remaining constant at its high temperature side in contrast to the abrupt decrease of LDPE. Moreover, the loss factor in the α relaxation region reaches its largest value for the composite of 8 vol% VGCF content. This means that the piezo-damping effect really functions in BaTiO 3 / VGCF /LDPE composites and only in certain conditions can this effect have practical significance. Further examination of the damping behavior in a different relaxation region demonstrates that the piezo-damping effect is directly related to the relaxation behavior of the polymeric matrix. Also, the piezo-damping effect is highly temperature and frequency dependent. The dielectric measurements suggest that, before the formation of a certain critical conducting state, the energy dissipation approach of the piezo-damping effect may be mainly determined by the interfacial polarization effect in the composite. Thus, it may be inferred that the piezo-damping effect also contributes to the dramatic increase of the loss factor at the high temperature side of the α relaxation peak for the BaTiO 3 /LDPE composite and functions practically even if there is no presence of VGCF.