Li0.5La0.5TiO3 (LLTO)/nano-Ag composite electrolytes were synthesized by a sol-gel process. Through the addition of nano-Ag powder with a relatively low melting point, the lattice parameter, grain size and morphology of LLTO-based electrolytes were tailored. The results revealed that Ag+ was oxidized into Ag+ during high-temperature sintering in air, and partial Ag+ entered into LLTO lattice and improved the bulk ionic conductivity. Meanwhile, owing to the liquid-phase-assisted grain growth induced by Ag, the grain size of LLTO was increased and the grain boundary conductivity was substantially improved. As a consequence, the bulk and grain boundary conductivities of LLTO were simultaneously enhanced through a facile nano-Ag combination, thereby leading to the highest total conductivity of 4.2 x 10(-5) S/cm in the sample with 5 wt% Ag, which is remarkably superior to that (2.8 x 10(-5) S/cm) of pure LLTO.