LiSbO3 modified 0.8(Na0.5Bi0.5)TiO3-0.2(K0.5Bi0.5)TiO3(abbreviated as NBT-KBT-LS) lead free piezoelectric ceramics were prepared by the solid state reaction method. The effect of LS content (0≤x≤1.50%) on the microstructure and electrical properties of the ceramics were studied carefully.It was found that all the NBT KBT LS samples exhibited a pure perovskite phase. The grain size of those materials increased after doping LS. Some large and plate like second phase appeared in such ceramic systems because some Bi3+ and Na+ volatilize due to the overheating at high temperature.The piezoelectric constant d33, electromechanical planar coupling factor kp,mechanical quality factor Qm, the remanent polarization Pr, the coercive field Ec were increased by doping appropriate amount of LS. It showed that the dopant of LS had “soft and hard double properties” dopant effect.The optimum electric properties (d33=154 pC/N,kp=0.268,Qm=107) could be found in the composition of x=0.75%.