Blue persistent luminescent β-Ga₂O₃: B₃₊ was synthesized by high solid-state reaction. The phosphor exhibits more than 0.5 h afterglow in the wavelength range of 380-600 nm after ceasing the ultraviolet light (260 nm) irradiation. The emission and excitation spectra, persistent luminescence decay curve, and thermoluminescence curve were measured. The emission and excitation spectra indicate that the B₃₊ doping improves on photoluminescent properties of β-Ga₂O₃. The thermoluminescence (TL) curve of β-Ga₂O₃: 80% B₃₊ shows that B₃₊ increased the traps and improved the depth of the traps.