The phase transition behavior and piezoelectric properties of (Ba1−xCax)(Zr0.1Ti0.9)O3 and (Ba0.85Ca0.15)(ZryTi1−y)O3 ceramics were investigated in this work to find out the potential factors contributing to large piezoelectricity. It was found that the morphotropic phase boundary (MPB) of (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 ceramics was closely related to the presence of an intermediate phase (considered as orthorhombic phase in this work) between rhombohedral (R) and tetragonal (T) phases at a narrow region, which could be carefully adjusted by the temperature and contents of Ca and Zr in the composition. In addition, the maximum piezoelectric and electromechanical coupling coefficients (with d33 = 572 pC/N and kp = 0.57) were observed near the MPB region close to T phase side, which might be intimately related to the presence of the intermediate phase. This investigation yielded a new sight to understand the mechanism of enhanced piezoelectricity near the MPB.