The 0.96(0.99K0.5Na0.5NbO3-0.01Bi0.5Na0.5TiO3)-0.04LiSbO3-xK4CuNb8O23(0≤x≤3.00%) (abbreviated as KNN-BNT-LS-KCN) lead-free piezoelectric ceramics were prepared by conventional solid-state reaction technique. The effects of K4CuNb8O23 on the crystal structure, piezoelectric, dielectric and ferroelectric properties of the ceramics were investigated. The results show that the crystal structure of prepared ceramics with no KCN is tetragonal symmetry, but that of the ceramics with KCN addition show orthorhombic symmetry at room temperature. A morphotropic phase boundary (MPB) between orthorhombic and tetragonal phases appeare near x=0.25% (mole fraction). The KCN-doped KNN-BNT-LS ceramics possess the properties of "hard" piezoelectrics. The KNN-BNT-LS ceramic doped with x(KCN)= 0.75% exhibites a high mechanical quality factor Qm (278) as well as relatively high piezoelectric constant d33(135 pC/N) and the electromechanical coupling factors kp(35.6%) and kt,(33.6%).%采用固相反应法制备了0.96(0.99K0.5Na0.5.5NbO3-0.01Bi0.5Na0.5TiO3)-0.04¨SbO3-xK4CuNb8O23(0≤x≤3.00％)(简称KNN-BNT-LS-KCN)无铅压电陶瓷，研究了其晶体结构、压电、介电以及铁电性质。结果表明，KCN的加入使所制陶瓷的晶体结构从四方相转变为斜方相，当KCN摩尔分数x在0.25％附近时，出现了准同型相界(MPB)。陶瓷表现出“硬性”掺杂特征，机械品质因数Qm显著提高。当x=0.75％时，Qm值达到了278，压电常数d33为135pC/N，机械耦合系数kp、kt分别为35.6％，33.6％。
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