Abstract: In recent years, high-resolution radiation detectors with direct coupling between new scintillators and CCD image sensors play an important role in improving the spatial resolution, detection efficiency, image quality and other performance indexes of Micro-CT and other high-resolution imaging systems. However, due to the micron pixel size of CCD and the isotropic luminescence and other characteristics of new scintillators such as Gd₃Al₂Ga₃O₁₂, it also brings serious crosstalk noise between the detector pixels, resulting in the difference between the actual and theoretical values of the spatial resolution of the radiation detector system. Firstly, the physical mechanism of crosstalk of high-resolution CCD radiation detector was systematically analyzed theoretically in this paper. Secondly, utilizing the tools such as Monte Carlo EGSnrc, Zemax and so on, the crosstalk rate function (CTF) was calculated theoretically. Then CTF was used for crosstalk correction of projected data. Finally, the image experiment of the dual-filament was implemented. It is illustrated that this method can effectively correct the crosstalk noise and improve the spatial resolution and modulation transfer function evidently for the high-resolution CCD radiation detector.