Nano-Ag particles/polyacrylamide (PAM) composites were synthesized by "y irradiation method and then blendedwith ethylene vinyl acetate (EVA). Dielectric behaviors of the Ag/PAM/EVA composites are investigated as a function ofboth the concentration and size of Ag particles. When concentration of the Ag fillers is rarely low, dielectric anomalieswere first observed in contrast to the traditional percolation theory. As concentration of Ag increases, volume resistivityand breakdown field strength are enhanced, loss tangent (tan δ) reduced and dielectric constant kept invariable. In addition,the above variation became larger when the diameter of the Ag nano-particles is smaller. Such dielectric anomalies may beunderstood by considering the unique "Coulomb Blockade Effect" of the nano-sized Ag particles.