High-performance solar-blind photodetectors have attracted significant attention due to their great significance in military and industrial applications. In this work, a high-performance self-powered solar-blind photodetector based on a MoS₂/β-Ga₂O₃ heterojunction was demonstrated. The photodetector exhibits a remarkable rectifying characteristic with a rectification ratio over 10⁵ and excellent solar-blind photoresponse properties with a cut-off wavelength of 260 nm and a high rejection ratio of 1.6 × 10³. Under light illumination of 245 nm (20.1 μW cm⁻²), the MoS₂/β-Ga₂O₃ heterojunction photodetector shows a responsivity of 2.05 mA W⁻¹ and a specific detectivity of 1.21 × 10¹¹ Jones at zero bias voltage. Such high-performances of this photodetector are superior to other previously reported β-Ga₂O₃ based photodetectors, and provide a guideline to design high-performance self-powered solar-blind photodetectors.