Recently, high-performance lead zirconate titanate (Pb(Zr1?xTi_x)O₃, PZT) ferroelectric ceramics have attracted intensive attention due to their wider operating temperature range, better temperature stability, as well as larger piezoelectric properties and higher energy conversion efficiency. In this study, the perovskite-type ferroelectric ceramics with a chemical formula of Pb0.99?xGd0.01Sr_xZr0.53Ti0.47O₃ (x=0 and 0.02, abbr. PGZT and PGSZT, respectively) were prepared by the traditional solid-state reaction route. The influences of Sr-doping on the phase structure, dielectric properties, ferroelectric properties and piezoelectric properties of the PGZT ceramics were comprehensively investigated. The field-dependent P–E hysteresis loops of PGSZT were measured in the frequency range of 0.05–10Hz and temperature range of 20–100^°C. The results show that Sr-doping not only enhances the dielectric permittivity and piezoelectric coefficient of PGZT, but also decreases its dielectric loss tangent, with the d33 value of 473pC/N, εr value of 1586 and tanδ value of 0.016 found in PGSZT. Also, PGSZT shows a high Curie temperature (TC) of 350°C. The underlying mechanisms of the property enhancement were identified as that the introduced Sr2+ replaces the volatile Pb2+ located at the A-site of the perovskite structure, thereby reducing the concentration of lead vacancies and promoting the grain growth of the ceramics, consequently enhancing the dielectric and piezoelectric properties of PGZT. On the other hand, the frequency change in the low-frequency range (<1Hz) played a significant impact on the remanent polarization (Pr) and internal biased electric field (Ei) of PGSZT, but the frequency dependence of coercive field (Ec) tends to diminish in the high-frequency range (≥1Hz).