Yttrium iron garnet (Y₃Fe₅O₁₂, YIG) materials with excellent magnetic and magneto-optical performances have been widely used in various fields such as the microwave communication, laser technology and optical fiber communication. Ion doping is considered as an effective method to improve the magneto-optical performance of YIG materials. In this study, Bi³⁺ with appropriate ion radius were selected to modify YIG ceramics to improve the magneto-optical properties of the materials. A series of Bi_xY_3-xFe₅O₁₂ (x=0, 0.3, 0.6, 0.9) ceramics were prepared by the hot-pressing sintering process with the solid-state reaction. Phase structure, micro-morphology, infrared transmittance, magnetic and magneto-optical properties of the sintered Bi_xY_3-xFe₅O₁₂ (x=0, 0.3, 0.6, 0.9) ceramics were investigated. All sintered Bi³⁺-doped YIG ceramic samples exhibit the pure garnet phase structure with dense microstructure, and the grain size increases with Bi³⁺ doping. The infrared transmittance of the sample is good, but it decreases with the increase of Bi³⁺ doping content. The Faraday rotation angle of the YIG ceramic sample changes linearly with the Bi³⁺ content increase. When the Bi³⁺ content increases about 1% (in atom), Faraday rotation angle changes about -49.0 (°)/cm and -30.2 (°)/cm at 1064 nm and 1550 nm wavelengths, respectively. Faraday rotation angles of Bi_0.6Y_2.4Fe₅O₁₂ ceramic sample at wavelengths of 1064 nm and 1550 nm are -703.3 (°)/cm and -461.5 (°)/cm, respectively, which are much higher than that of the undoped YIG ceramics (277.6 (°)/cm and 172.0 (°)/cm, respectively). The magneto-optical performance of YIG ceramics is enhanced obviously by the Bi³⁺ doping.