In this work, a new Ce∶GAGG scintillation crystal is coupled with the CR-173 photomultiplier tube, and then is packaged in an aluminum alloy shell together with voltage divider circuit, high voltage module and preamplifier circuit to fabricate a novel Ce∶GAGG scintillation detector. The effects of different sizes of Ce∶GAGG scintillation crystals, different coupling modes and different reflective layer packaging materials on the light yield and energy resolution of the Ce∶ GAGG scintillation detector are studied, at the same time, it is compared with the packaged 1 inch (1 inch=2.54 cm) thallium doped sodium iodide (NaI(Tl)) scintillation crystal, and the energy linearity of Ce∶GAGG and NaI(Tl) scintillation detectors is measured. The experimental results show that the small size of Ce∶GAGG scintillation detector has the best performance;the optical silicone coupling can significantly improve the performance of the scintillation detector; the enhanced specular reflector (ESR) material packaging scintillation detector has the best performance; the performance of Ce∶GAGG scintillation detector is better than NaI(Tl) scintillation detector.