X-ray detection and imaging technology, as a crucial tool for modern material analysis, has been widely implemented in medical diagnosis, industrial non-destructive testing, and aerospace precision analysis. This review focuses on the core components of X-ray detection systems—photoelectric conversion materials and device architectures, systematically summarizing recent research progress of metal halide semiconductors in this field. These materials demonstrate exceptional X-ray attenuation capabilities and long carrier diffusion lengths due to their high atomic numbers. Combined with solution processability that enables low-cost manufacturing, they show tremendous potential for next-generation radiation detection. We first introduce the interaction mechanisms between metal halides and X-ray. Then, we enumerate key parameters affecting detection and imaging performance, thoroughly discussing strategies to optimize detection performance through material design and device engineering, covering both direct and indirect X-ray detection approaches. Finally, we summarize the main challenges facing current X-ray detectors and their potential solutions, followed by perspectives on future development.