β-Ga₂O₃, a semiconductor with a wide bandgap, has garnered significant attention from researchers owing to its remarkable optoelectronic properties. The exploration of how elemental doping affects the spectral properties of β-Ga₂O₃ constitutes a pivotal research area within materials science, offering substantial research value and promising application prospects. In this study, β-Ga₂O₃∶6%Bi single crystal was successfully synthesized in the CO₂ atmosphere through the utilization of the optical floating zone (OFZ) method. The primary focus of this investigation was to delve into the spectral properties of the Bi-doped β-Ga₂O₃ single crystal. To gain a thorough understanding of the samples, a battery of sophisticated characterization techniques was employed. These included X-ray diffraction (XRD) for analyzing the crystal structure, Raman spectroscopy for probing vibrational modes, scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDS) for examining surface morphology and elemental composition, X-ray photoelectron spectroscopy (XPS) for determining chemical states, and both transmission and fluorescence spectroscopy for assessing optical properties. The experimental outcomes unveiled that it is difficult for Bi ions to be doped into the β-Ga₂O₃ crystal lattice due to the large difference in ionic radii. The doped Bi ions predominantly occupied the sites of Ga ions within the GaO₆ octahedra. Compared with unintentionally doped β-Ga₂O₃, Bi-doped β-Ga₂O₃ single crystals exhibit a decrease in transmittance in the infrared region and an increase in carrier concentration; the emission spectral intensity is reduced, and the fluorescence decay time is shortened. These groundbreaking discoveries not only enhance our comprehension of the spectral properties of Bi-doped β-Ga₂O₃ single crystals but also offer technical insights for the potential application of this material in diverse fields, including scintillator materials and radiation detection systems.