Ion substitution was the most efficient way for BiFeO₃ modification. In this work, polar Na_0.5Bi_0.5TiO₃ and non-polar CaTiO₃ were chosen to modify BiFeO₃, and the effects of Na_0.5Bi_0.5TiO₃ and CaTiO₃ co-substitution on the crystal structure, dielectric, ferroelectric and magnetic properties of BiFeO₃ ceramics were investigated. All ceramics exhibited rhombohedral R3c phase with dense microstructure. Two dielectric anomalies were observed, one related to the valence change of Fe ions and the other to the ferroelectric phase transition. The DSC and dielectric analysis confirmed that the Curie temperature T_C linearly increased with increasing Na_0.5Bi_0.5TiO₃ content, while the magnetic transition temperature T_N nearly unchanged. Meanwhile, the leakage current of the ceramic samples with Na⁺ was three orders of magnitude lower than that of a sample without Na⁺ ion. Due to the decrease in leakage current density, the breakdown field strength and piezoelectric properties were improved. In addition, the magnetic properties of all co-substituted ceramics were improved to a certain extent, which indicated that the co-doping of A-site and B-site affected the magnetic properties of the present ceramics.