Fabrication conditions, involving the introduction of intrinsic defects such as oxygen vacancies in the material, play a crucial role in the persistent luminescence (PersL) properties. In this study, Y₃Al₂Ga₃O₁₂ (YAGG):Pr³⁺ ceramic phosphors were synthesized in the air from 1400 to 1600 °C by using a solid-state reaction method. The influence of sintering temperature on luminescence properties and PersL properties was investigated. YAGG:Pr³⁺ prepared via a low sintering temperature (1400 °C) exhibits the relative strongest 5d-4f photoluminescence and PersL in the UV region of Pr³⁺ among the samples. The Thermoluminescence (TL) measurements revealed that the intensity of two strong TL peaks related to intrinsic trap centers increases with the rise in sintering temperature. A significant reduction in deep traps, associated with the oxygen vacancies in the sample sintered at 1400 °C, can be observed in the normalized TL glow curves. Consequently, the enhancement of UV PersL of Pr³⁺ was observed which may through suppressing the relaxation process from the 5d state to ¹D₂ level through the state of intrinsic defects.