Lead-free piezoelectric ceramics Ba1-xCaxTi1-yZryO3+1mol%CuO were prepared by an ordinary sintering technique and the effects of Ca2+ and Zr4+ on phase transition and electrical properties of the ceramics were studied. The results of X-ray diffraction show that the ceramics exhibit a pure perovskite structure at 0 <= x <= 0.175 and 0 <= y <= 0.175, suggesting that Ca2+ and Zr4+ diffuse into BaTiO3 lattices to form a solid solution. The substitution of Zr4+ for the B-site Ti4+ ions of BaTiO3 decreases greatly Curie temperature T-C and strengthens the relaxor character of the ceramics, while the addition of Ca2+ has a weak influence on T-C and leads to an inhibition of grain growth. Owing to the more possible polarization states resulting from the coexistence of tetragonal and orthorhombic phases near room temperature, the ceramics with x = 0.075-0.125 and y = 0.1 exhibit excellent piezoelectric properties: d(33) = 254-345 pC/N and k(p) = 38.0-45.2%, respectively. (C) 2012 Elsevier B.V. All rights reserved.