0.96(Na,K)(Nb0.9Ta0.1)O3–0.04LiSbO3 powders in the orthorhombic phase were synthesized in the molten salt KCl at a low temperature 800 °C. It was revealed that K+ in the molten salt tended to substitute Na+ in the A-sites and the final product 0.96(Na0.29K0.71)(Nb0.9Ta0.1)O3–0.04LiSbO3 was synthesized from the nominal composition 0.96(Na0.5K0.5)(Nb0.9Ta0.1)O3–0.04LiSbO3. The dense ceramics under pressureless were obtained by sintering in the air. The ceramics exhibited high piezoelectric constant d33 of 239 pC/N and good remnant polarization Pr of 30.79 μC/cm2 with coercive electric field Ec of 2.01 kV/mm. And leakage current was reduced by muffling the ceramics with the as-prepared powders during the sintering process.