A novel near-infrared long afterglow material of Zn₃Ga3.99GexO9+2x :1%Cr³⁺ (x=1,2,3,4,5) were synthesized by a conventional high-temperature solid-state reaction method in this paper.Crystal structure, photoluminescence (PL) and afterglow properties of the prepared phosphors were a nalyzed by X-ray diffraction (XRD) and fluorescence spectrometer.The Zn₃Ga3.99Cr0.01GexO9+2x sample is a solid solution in which Cr³⁺ and Ge⁴⁺ replace partially Ga³⁺ of ZnGa₂O₄:Cr³⁺ spinel structure.The samples can emit the strong red and near-infrared light in the range of 640~720nm by near-ultraviolet and blue-green light excitation.The st rongest emission peak lies at 695nm, which belongs to the Cr³⁺ ion emission (²E→⁴A₂ transition).All samples show bright and super-long afterglow luminescence in the near-infrared region more than 300h.The effects of sintering temperature on luminescence and afterglow performance of th e samples are analyzed.The results show that PL and afterglow luminescence intensities gra dually increase with raising temperature of sintering,and the optimum sintering temperature of Zn₃Ga3.99Cr0.01Ge₁O₁₁ phosphor is 1200℃.