Ag nanoparticles were prepared via a wet chemical reduction method and treated with tetraethoxysilane (TEOS) to form an insulating SiO2 layer on the surface (Ag@SiO2). The Ag@SiO2 nanoparticles were introduced in to the BaTiO3/poly (vinylidene fluoride) matrix to prepare the three-phase Ag@SiO2/BaTiO3/poly (vinylidene fluoride) composite, and the dielectric behavior of the composite was investigated. The results showed that the typical “conductor/polymer” percolation effect was not observed in the composite as a result of the SiO2 layer, which prevented Ag particles from contacting with each other directly and restricted the movement of electrons under external field. The high dielectric constant of 723 and a relatively low loss of 0.82 were achieved at 100 Hz with 40 vol% Ag@SiO2 and 20 vol% BaTiO3, respectively. The microcapacitor network model and “Maxwell-Wagner-Sillars” (MWS) effect were used to investigate dielectric properties of the three-phase composite.