Lead halide perovskite nanocrystal materials such as CsPbX3 (X = Cl, Br, and I) have triggered an intense research upsurge due to their excellent scintillation performance. Herein, an in situ crystallization strategy is developed to grow CsPbBr3 nanocrystals (NCs) within a low-melting-point (280 °C) coordination polymer (CP) glass. The viscosity of coordination glass is reduced through a low-temperature (e.g., 50 °C) thermal treatment, enabling the short-distance migration of uniformly dispersed ions (Cs+, Pb2+, and Br-) to achieve in situ crystallization of CsPbBr3 NCs. Benefiting from the high transmittance (80% within the 500-800 nm range) and outstanding scintillation performance, the prepared CsPbBr3@ZnBr2(bIm+DMSO)2 (bIm = benzimidazole, DMSO = dimethyl sulfoxide) transparent luminescence glass exhibits an excellent X-ray imaging resolution of up to 25 lp/mm, outperforming many perovskite glass and crystalline scintillators. This work would provide an idea for the development of high-resolution scintillation screens that can be prepared at low temperatures.