CsPbBr₃ crystal has emerged as a promising candidate material for next-generation semiconductor radiation detectors due to its high atomic number， excellent charge transport properties， and room-temperature operability. However， defects in the crystal （point defects， twins， and secondary phases） significantly degrade its performance. This review systematically analyzes the formation mechanisms of defects in CsPbBr₃ and their impact on carrier transport， lattice polaron effects dominate intrinsic scattering while point defects （e.g.， Pb interstitials） introduce deep-level traps that enhance carrier recombination， ferroelastic domains （twins） induce carrier localization through interfacial potential barriers， and secondary phases （e.g.， CsPb₂Br₅） reduce mobility and resistivity via light scattering and incoherent interfaces. The study highlights differences in defect distribution between melt- and solution-grown crystals and proposes optimization strategies such as stoichiometric control， solvent engineering， and annealing. Although CsPbBr₃ demonstrates X/γ-ray energy resolution comparable to commercial CdZnTe （e.g.， 1.4%@662 keV）， defect dynamics and ion migration hinder stability. Future research should focus on elucidating polaron-defect interactions， developing defect suppression techniques， and designing novel device architectures to advance its applications in nuclear medicine imaging and deep-space exploration.