Radiation detection, converting high-energy (keV) photons to lower energy (1.7-3 eV) photons, is of great importance in various fields, including medical diagnostics, quality inspection, and security checking. High-resolution scintillation imaging based on lead halide perovskite nanocrystals is very promising for these applications owing to their high absorption cross-section for X-rays, fast decay time, room temperature fabrication, tunable bandgap, low trap density, and near-unity photoluminescence quantum yield. Although considerable achievements have been obtained, challenges remain for future industrialization. Herein, the progress of scintillators based on lead halide perovskite nanocrystals is reviewed, including their working mechanism, key parameters, and the relationship between growth condition and performance. An overview of the current state of the art in this promising research area toward high-performance X-ray scintillators is provided, along with a look at some of the challenges and opportunities that lie ahead.