Organometallic halides have shown great potential in X-ray imaging. However， problems such as poor uniformity， low transmittance and light scattering of polycrystalline thin film scintillator screens seriously reduce the X-ray imaging resolution. In this paper， inch-size （C₂₄H₂₀P）₂MnBr₄ single crystalline film was prepared by the space confinement method， and the phase， optical and scintillation properties were studied. This crystal exhibits a photoluminescence quantum yield （PLQY） of 90% and excellent photostability. After continuous irradiation of the crystal with 365 nm ultraviolet light for 24 h， its spectrum remains stable. Based on the excellent optical properties of this crystal， a high light yield of 83 000 photons/MeV （estimated value） is generated under X-rays， which is 2.5 times higher than that of commercial LYSO scintillator. In addition， this crystal exhibits excellent radiation stability and maintains its performance stability even after being exposed to a high dose rate of 504 mGy·s^-1 for 60 min. Based on the above advantages， the （C₂₄H₂₀P）₂MnBr₄ single crystalline film is applied into X-ray imaging， achieving a spatial resolution of approximately 23 lp/mm， demonstrating great application potential in this field.