The electron structure of the Na_1/2Bi_1/2TiO₃ system with ABO₃ type perovskite structure is studied by using self-consult charge-discrete variation-X_α (SCC-DV-X_α) method, and the effect of A, B position substitute on poling characteristic is also analyzed. The calculational results show that spontaneous polarization exists in the NBT piezoceramics system, the piezoelectric properties are enhanced because of the displacement of the B position ions, in addition, the compound substituent of Ba, Sr and Mn ion can decrease coercive field, and increase the strength of spontaneous polarization, so the dielectric properties get improved.