Pb0.96Sr0.04(Zr,Ti)0.7(Zn1/3Nb2/3)0.3O₃ (PZN–PZT) piezoceramics with various Zr/Ti ratios and Li₂CO₃ sintering aid were sintered at 900^∘C by the solid-state reaction route. The samples with different Zr/Ti ratios were compared according to microstructure, phase structure, piezoelectricity, ferroelectricity, and dielectric relaxation. The Zr/Ti ratio in the PZN–PZT ceramics greatly affects the electrical properties. The Zr/Ti ratio affects the proportion between the rhombohedral and tetragonal phases and also affects the grain size. The PZN–PZT ceramics with the Zr/Ti ratio of 53:47 have the largest grain size and have optimized piezoelectric properties (kp = 0.58, d33 = 540 pC/N, and TC = 250^∘C). The larger the grain size, the lesser the grain boundary, the easier the domain wall motion, and the better the piezoelectric properties. The PZT ceramic with Zr/Ti ratio of 53:47 locates the morphotropic phase boundary (MPB) region which is one of the key factors for the high piezoelectric properties of the PZT.Pb0.96Sr0.04(Zr,Ti)0.7(Zn1/3Nb2/3)0.3O₃ (PZN–PZT) piezoceramics with various Zr/Ti ratios and Li₂CO₃ sintering aid were sintered at 900^∘C by the solid-state reaction route. The samples with different Zr/Ti ratios were compared according to microstructure, phase structure, piezoelectricity, ferroelectricity, and dielectric relaxation. The Zr/Ti ratio in the PZN–PZT ceramics greatly affects the electrical properties. The Zr/Ti ratio affects the proportion between the rhombohedral and tetragonal phases and also affects the grain size. The PZN–PZT ceramics with the Zr/Ti ratio of 53:47 have the largest grain size and have optimized piezoelectric properties (kp = 0.58, d33 = 540 pC/N, and TC = 250^∘C). The larger the grain size, the lesser the grain boundary, the easier the domain wall motion, and the better the piezoelectric properties. The PZT ceramic with Zr/Ti ratio of 53:47 locates the morphotropic phase boundary (MPB) region which is one of the key factors for the high piezoelectric properties of the PZT.