The dielectric property varies significantly with the B-site cations in ABO3 perovskite-type oxides. In this study, we tried to understand the difference in the dielectric properties between SrTiO3 (STO, εr = 290, Qf = 3,000 GHz) and SrZrO3 (SZO, εr = 30, Qf= 13,700 GHz) by measuring dielectric spectroscopy of their solid solutions in a wide frequency range. The dielectric permittivity and the loss tangent (tan δ) of SrZrxTi1-xO 3 (STZ, 0.0 ≦ × ≦ 1.0) ceramics were evaluated up to GHz region using planer electrode method and ring resonator method. The four-parameter-semi-quantum (FPSQ) model was employed to analyze the Infrared-reflectivity (TR-reflectivity) data of STZ ceramics. Both dielectric properties up to GHz region and IR reflectivity in THz region were incorporated in the analysis to accurately determine the optical phonon parameters. Ultra wide band dielectric spectra of STZ ceramics and STO single crystal were presented. The ionic polarization dominantly determined the dielectric permittivity of STZ ceramics and STO single crystal. High permittivity of STO was due to the Slater mode. The decrease of dielectric permittivity and g-factor (=1/tan δ) with increasing Zr content (x) in STZ ceramics was attributed to the depression of the Slater mode. The effect of optical phonon parameters on the permittivity and tan 8 in microwave region was simulated to generalize the results obtained for STZ ceramics.