X-ray detectors play a vital role in medical diagnostics， security screening， industrial nondestructive testing， and scientific research. Halide perovskites （HPs） have garnered significant attention for high-performance X-ray detection due to their large X-ray absorption coefficient， long carrier diffusion length， and superior optical properties. Notably， the flexible synthesis of HPs enables facile fabrication into polycrystalline films， wafers， and other forms. However， differences in crystallization behavior induced by fabrication methods result in varied defect distributions within the active layer， such as crystallographic orientation， grain boundaries， cracks， and pinholes， which critically impact charge carrier transport and scintillation efficiency and degrade the device performance. Therefore， elucidating crystallization mechanisms under different fabrication conditions and developing tailored control strategies are imperative. Here we systematically review the recent advances in HPs X-ray detectors： 1） wet chemical synthesis approaches and crystallization regulation strategies； 2） crystallization regulation in pressing methods， ion migration suppression， and scintillator wafer development； 3） analyzing crystallization mechanisms in vapor deposition processes， strategies for enhancing scintillator performance， and exploratory efforts toward direct X-ray detection applications. Finally， we highlight existing challenges and future prospects for advancing HPs X-ray detectors.