Influence of nonstoichiometry and doping on piezoelectric properties and depolarization temperature of lead-free piezoelectric ceramics (Na1/2Bi1/2)0.92Ba0.08TiO3 was studied. Nonstoichiometry of A-site can improve their piezoelectric properties. Doping in B-site has great influence on electric properties, which is similar to the corresponding rules of Pb(Ti,Zr)O3-based ceramics. Variation of coupling effect of A-site cation on BO6 octahedra as results of nonstoichiometry, and the doping in NBBT ceramics leads to variations of the depolarization temperature. The higher the depolarization temperature of Na1/2Bi1/2 TiO3-BaTiO3 ceramics studied,the lower the piezoelectric constant.