Pb(Ni,Nb)O3-Pb(Zr, Ti)O3 (hereafter PNN-PZT) ceramics were prepared using two type of columbite precursor and effect of CuO addition on microstructure dielectric and piezoelectric properties was investigated in the vicinity of MPB. CuO acted as sintering aids by the reaction with PbO which increased the amount of liquid phase and densification of PNN-PZT. The second phase formation and PbO volatilization which was detrimental to both dielectric and piezoeletric properties were suppressed. Especially the columbite precursor heat-treated at high temperature (120$0^{circ}C$) showed more homogeneous grain size lower PbO volatilization higher density and more desiable electrical properties than those of samples prepared at low temperature (100$0^{circ}C$) heat-treated one. By the addition of CuO sintering temperature of the system was lowered from 125$0^{circ}C$ to 100$0^{circ}C$ and the temperature dependence of piezoelectric constant of the specimens was decreased due to the increase of the curie temperature (Tc) As high-heat treated precursor was sintered with the addition of 0.8mol% CuO at 100$0^{circ}C$ for 2 h the specimen showed the electrical properties of $varepsilon$r=4400 kp=0.53 Qm=78,