Ba0.8Sr0.2TiO3 (BST) nanopowder was successfully synthesized by Pechini sol-gel method under different temperatures. Not only were BaCO3 impurity phase production and transition temperature from cubic to tetragonal phase respectively set at 440 °C and 800 °C, but also barium (Ba) resided in a 12-coordinate site of crystal lattice was set at 580 °C by the techniques of X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). In addition, gels at pH 3–8 were used to prepare BST ceramics and the ceramics morphology was characterized by scanning electron microscope (SEM). The interrelationship between morphology and electrical properties, which were associated with precipitation phase on the crystal boundary of BST ceramics, was studied in detail. Finally, the optimal electrical properties of the ceramics were comprehensively displayed in this work, i.e., er = 8113.81, d33 = 78 pC/N, kp = 14.96%, and Qm = 85.08 at pH 5.