X-ray scintillators have been widely used in many fields owing to their strong penetrating ability, including security inspection, medical imaging, nuclear cameras, high energy physics and so forth. To explore new scintillation materials, we designed and synthesized KGW:Tb bulk scintillation crystals with monoclinic phase structure. We explored the fluorescence performance of KGW:Tb by testing the photoluminescence spectrum and fluorescence decay curve and observed strong green light emission in the visible light range at room temperature. Moreover, our crystal has a high stability under X-ray irradiation, a good sensitivity response and an appreciable light output (3424 ph/MeV) that is approximately twenty times more than PbWO₄. Moreover, we used a 0.98 mm thickness polished crystal sheet for X-ray imaging applications and observed excellent results. Therefore, KGW:Tb crystal may be an important direction for X-ray scintillation detection.