The degradation of barium titanate ceramics was studied under the high AC electric field. At 150$^{circ}C$, life time was measured as a function of grain size, controlled by varying sintering time at 1375$^{circ}C$ and electrical properties, such as AC conductivity, capacitance and dissipation factor, were measured during degradation process. The life time decreased as grain size increased in the range of 2.44-8.23$mu extrm{m}$. The AC conductivity was remained constant and increased suddenly at the last stage of degradation process. The capacitance was slowly decreased and the dissipation factor was slowly increased as the degradaton progressed.