The 0.75Pb(Zr1/2Ti1/2)O3-xPb(Zn1/3Nb2/3)O3-(0.25-x)Pb(Ni1/3Nb2/3)O3 (0.75PZT-xPZN-(0.25-x)PNN, x = 0.05, 0.10, 0.15, 0.20) ceramics were prepared with conventional solid-state method, the effects of different x values on the crystal structure, sintering characteristics,microstructure, and the dielectric,ferroelectric,piezoelectric properties of ceramics were investigated.The result showed that the rhombohedral and tetragonal phases coexisted in the ceramics and the components were located near the MPB when x= 0.10~0.20. As the PZN content increased, the rhombohedral phase decreased, the tetragonal phase increased, and the dielectric constant (εT), piezoelectric constant (d33), electromechanical coupling coefficient (kp) and transduction coefficient(d33×g33) increased firstly and then decreased.When x=0.15, the ceramics with the composition of 0.75PZT-0.15PZN-0.10PNN showed excellent properties with εT = 1 850, tan δ=0.029, TC= 280 ℃, d33=370 pC/N, and kp=0.67.