In the article, PVDF-based composites reinforced by MWCNT and phenolic epoxy resin were prepared by solution casting method to get a material with excellent mechanical properties and high dielectric properties and breakdown strength when conductor is as filler. The experimental results demonstrate that dielectric constant of m-MWCNT/EP/PVDF composites (εr = 32 at 100 Hz) is twice times higher than that of the EP/PVDF composites, and is about three times higher than that of the pure PVDF. The dielectric loss is not higher than that of the others (Tan δ = 0.3 at 100 Hz). The breakdown strength of the composites is higher than 100 MV/m, which is superior to most of composites modified with conductors. The breakdown strength for most of composites modified with conductors is under 100 MV/m. The elongation at break of m-MWCNT/EP/PVDF composites keeps 500% and the tensile yield strength increases continuously.