The phase transition and pyroelectric behavior of NayBiz Ti1-xO3(1-x)-xBaTiO(3) (x = 0.06-0.08, z/y >= 1) ceramics were investigated as functions of temperature and electric field. A dominant antiferroelectric (AFE) ground state is proposed for NayBizTi1-xO3(1-x)-xBaTiO(3) (x = 0.06-0.08, z/y >= 1) ceramics at room temperature ( RT). The stability of the induced ferroelectric (FE) phase is closely related to the molar ratio of Na+ and Bi3+. The temperature of the FE to AFE phase transition for the poled samples can be adjusted to RT through a modulation of the molar ratio of Na+ and Bi3+. Pyroelectric current peaks were detected at the FE-AFE transition temperature. Huge pyroelectric coefficients of 905 x 10(-8), 3270 x 10(-8), and 140 x 10(-8)degrees C. (cm(2).K)(-1) were obtained at phase transition temperatures of 83 degrees, 64 degrees, and 34 degrees C, respectively.