Novel percolative PZN-PZT/Ag ferroelectric composites with intragranular structure were prepared with micro-PZN-PZT and nano-Ag particles. The typical core-shell nanostructures were systematically investigated by TEM, in which, the nanoscale shells act as interlayers between the Ag cores and the ceramic matrix. Excellent dielectric properties, such as high dielectric constant (epsilon(r) similar to 16600) and low dielectric loss (< 0.056) were reported. The high dielectric constant originates from the coeffect of microcapacitors and Maxwell-Wager-Sillars (MWS) polarization. Especially, the core-shell structure may reinforce the MWS effect. Meanwhile, the insulating interlayers reduce the tunnel current between neighboring Ag cores by causing potential barriers, endowing the nanocomposites with low dielectric loss. This approach can be used to realize a novel material with high dielectric constant over a wide frequency and temperature range.