(1-x)Bi0.5(Na0.82K0.18)0.5TiO3-xNaNbO3((1-x)BNKT-xNN）leadfree piezoelectric ceramics were prepared by solid state reaction method.The effect of composition on the phase, microstructure and electricproperties were studied.The results show that the calcination temperature is 900 ℃ by thermal analysis.By XRD detecting,the calcinated powder are all perovskite structures and all ferroelectric orthogonal phase at precalcination temperature of 900 ℃.By SEM,The grain size is enhanced with the NN content increasing. The excellent electric properties of εT33/ε0=1 400，tanδ=0.05, d33=138pC/N,kp=0.40 are obtained with NN content of x=0.02 at the sintering temperature of 1 200 ℃.