The (K0.5Na0.5)0.98Li0.02Nb0.77Ta0.18Sb0.05O3 (LTS-KNN) lead-free piezoelectric ceramics are successfully prepared by the traditional solid-state method at the sintering range of 1 110-1 150 ℃. All samples show good crystallinity without second phase. The piezoelectric ceramics sintered at 1 130 ℃ are well-densified and have good piezoelectric properties. By adjusting the polarization electric field and polarization temperature, the polarization degree of the ceramics can be improved, and the piezoelectric properties are optimized. The experimental results show that when the sintering temperature is 1 130 ℃, the polarization electric field is 3 kV/mm and the polarization temperature id 60 ℃, the best piezoelectric performances have been obtained, that is, the piezoelectric constant d33 =310 pC/N, the electromechanical coupling coefficient kp=48%.