Lead-free 0.955K(0.5)Na(0.5)Nb(1-z)Ta(z)O(3)-0.045Bi(0.5)Na(0.5)ZrO(3)+0.4%MnO ceramics (abbreviated as KNNTaz-0.045BNZ+0.4Mn) were prepared by a conventional solid-state sintering method in a reducing atmosphere (oxygen partial pressure of 1x10(-10)atm). All ceramics with a pure perovskite structure show the two-phase coexistence zone composed of rhombohedral and tetragonal phase. Ta5+ ions substitute for Nb5+ ions on the B-site, which results in a decrease in the R phase fraction in the two-phase coexistence zone. The R-T phase transition temperature moves to room temperature due to the substitution of Nb5+ ions by Ta5+ ions. A complex domain structure composed of small nano-domains (similar to 70nm) formed inside large submicron domains (similar to 200nm) exists in KNNTa0.02-0.045BNZ+0.4Mn ceramics, which can induce a strong dielectric-diffused behavior and improve the piezoelectric properties. The temperature stability for the reverse piezoelectric constant for the KNNTaz-0.045BNZ+0.4Mn ceramics can be improved at z=0.02. Excellent piezoelectric properties (d(33)=328 pC/N, and =475pm/V at E-max=20kV/cm) were obtained for the KNNTa0.02-0.045BNZ+0.4Mn ceramics.