Effects of 0.5 wt% CuO addition on the sintering, structural and electrical properties of perovskite layer structured (PLS) Sr2Nb2O7 ceramics prepared by solid-state reaction method are investigated. The addition of CuO is beneficial to the liquid phase bridge formation at sintering process, leading to lower sintering temperature of 1180 degrees C and larger bulk density up to 98%. Meanwhile, CuO modified Sr2Nb2O7 ceramics show a remarkable d(33) of (1.1 +/- 0.1) pC/N while still with a very high T-c of (1340 +/- 2)degrees C. Raman spectra indicate that the improvement of piezoelectricity could be attributed to the rotation and/or distortion of oxygen octahedron caused by possible Cu2+ substitution at the A-sites of Sr2Nb2O7.