Mn-added 0.3BaTiO30.1Bix(Mg1/2Ti1/2)O30.6BiFeO3 (x = 0.93, 0.96, 1.00, 1.04, 1.07, and 1.10) ceramics were fabricated by conventional solid-state reaction. The crystal systems of all the ceramics were pseudo-cubic, and no secondary phase was observed. It was found that the ceramics with x = 1.00 exhibited an optimum piezoelectric property of d33 = 106.16 pC/N, while the Bi-deficient and excess ceramics lowered the piezoelectric properties to 81.09 and 102.29 pC/N, respectively. The reason of the decreases could be associated with domain wall pinning effects by defect complexes and the presence of the residual small amount of Bi2O3. ©2019 The Ceramic Society of Japan. All rights reserved.