The effects of a small amount MnO2 (0-120 mol%) doping on the phase transition behavior, microstructure and electrical properties of(K0.5Na0.5)(0.94)Li0.06NbO3 (KNLN6)ceramics have been investigated X-ray diffraction analysis showed that the ceramics underwent a perovskite structure transition from tetragonal to orthorhombic symmetry with increasing the MnO2 content, which is similar to the morphtropic phase boundary (MPB) SEM and density studies revealed that a small amount of MnO2 improved effectively the densification of the KNLN6 ceramics Because of the high densification, the mechanical quality factor Q(m) of the KNLN6 ceramics were significantly enhanced by MnO2 addition which meant MnO2-doping changed the KNLN6 to "hard" ceramics. For 1.20 mol% MnO2-doped KNLN6 ceramics, the mechanical quality factor Q(m) reached up to 301, which increased by four times as compared with KNLN6. The piezoelectric constant d(33) and the planar electromechanical coefficient k(p) still maintained relatively high levels. which were about 141 pC/N and 32.0%. respectively (C) 2009 Elsevier B.V All rights reserved.