Gallium oxide (Ga₂O₃), a semiconductor material with a wide bandgap (approximately 4.9 eV) and unique optoelectronic properties, has attracted significant attention in recent years for applications in ultraviolet photodetectors (UVPD), photodetectors, and optoelectronic sensors. Ga₂O₃’s micro/nano structures, such as nanowires, nanorods, nanotubes, and nanosheets, exhibit excellent optoelectronic response characteristics, fast electron mobility, and high stability, making them crucial for enhancing the performance of detectors. This paper introduces various synthesis methods for Ga₂O₃ micro/nano structures, including hydrothermal, electrochemical deposition, and vapor deposition methods. The advantages and disadvantages of these techniques are analyzed, and how to achieve precise control over the morphology and size of Ga₂O₃ micro/nano structures by adjusting reaction conditions is discussed. Furthermore, the application of these micro/nano structures in ultraviolet photodetectors is explored, particularly their potential in high-sensitivity, high-selectivity, and polarization-sensitive optoelectronic detectors.