The effect of Ba0.7Ca0.3TiO3 (BCT) substitution on the structural, dielectric, ferroelectric, and piezoelectric properties of mechano-chemically synthesized lead-free (1-x)Ba0.9Sr0.1TiO3-(x)Ba0.7Ca0.3TiO3 (x=0.0, 0.10, 0.20, 0.35, and 0.50) ceramics have been investigated. XRD patterns confirms the formation of tetragonal phase with P4mm space group. The results indicate a strong influence of BCT substitution on the structural and electrical properties of Ba0.9Sr0.1TiO3 (BST) ceramic. BSTBCT ceramic for x=0.35 have shown high dielectric constant epsilon(m)similar to 21 800, high remnant polarization P-r similar to 10.16 mu C/cm(2), large piezoelectric charge constant D-33 similar to 293 pC/N, large piezoelectric voltage constant g(33)similar to 5.80 mVm/N, and highest dielectric breakdown strength E-bd similar to 224 kV/cm among the five synthesized samples. The correlation between structural, dielectric, ferroelectric, and piezoelectric properties of the BST ceramic with increasing BCT content have been systematically described on the basis of domain wall motion and grain size effect.