Ce³⁺ and Eu²⁺ doped and Ce³⁺-Eu²⁺ co-doped Sr₂MgSi₂O₇ phosphors are prepared via a high-temperature solid-state reaction technique. The synchrotron radiation vacuum ultraviolet-ultraviolet (VUV-UV) excitation and ultraviolet-visible (UV-vis) emission spectra of diluted Ce³⁺ and Eu²⁺ doped Sr₂MgSi₂O₇ samples are measured at cryogenic temperatures. The electron-vibrational interaction (EVI) between Ce³⁺ and its surroundings is analyzed. The dependencies of the 4f-5d transitions of Ce³⁺ on the structure of the host compounds Sr₂MgSi₂O₇, Ba₂MgSi₂O₇ and BaMg₂Si₂O₇ are discussed in detail. Then the thermal quenching channel is proposed based on the measurements of temperature dependent luminescence intensities and decay times of Ce³⁺ and Eu²⁺ in Sr₂MgSi₂O₇, and the Ce³⁺ → Eu²⁺ energy transfer mechanism is understood by three luminescence dynamic models. In addition, Sr₂MgSi₂O₇:Ce³⁺/Eu²⁺ samples are evaluated for the possibilities of X-ray detection applications using X-ray excited luminescence (XEL) spectroscopy, and it was found that they are not suitable.