Multiferroic BiFeO3 and Bi0.92Dy0.08FeO3 ceramics were prepared to study their crystal structures and piezoelectric properties. BiFeO3 exhibits rhombohedral phase below 810 °C. Although Bi0.92Dy0.08FeO3 ceramic also shows rhombohedral phase at room temperature, it allows the coexistence of rhombohedral phase and orthorhombic phase at 460–650 °C. Both samples have maximum polarizations of >21 μC/cm2 and piezoelectric d33 values of ∼37 pC/N at room temperature. Their polarized slices show the dielectric anomalies and impedance anomalies because of vibrating resonances below 500 °C, and the thickness vibration electromechanical coupling factor is ∼0.6 and ∼0.4 for BiFeO3 and Bi0.92Dy0.08FeO3, respectively. The vibrating resonances confirm piezoelectric responses. Furthermore, samples' impedance and resistance decrease fast with temperature increasing, which screens piezoelectric response above 550 °C.