Objective:To explore the relationship between the conditions of exposure, the size of IP and the spatial resolution in CR.Methods:Based on Siemens, figured out the several exposure conditions of hands' under the same energy. Four various IP sizes and large or small focuses are used to radiograph of the X-ray patterns. The values of the spatial resolution are read and analyzed by no-magnification or 2-time magnification technology to get out the influences on the spatial resolutions of CR system.Results:First, the value of spatial resolution with small focus is high than with the large focus. Second, the values of spatial resolution of CR will be reduced when the imaging plate turns larger. Third,the spatial resolution of two magnification CR images is higher than the resolution of no magnified images. Last, a proper condition of exposure can improve the spatial resolution of CR images.Conclusion:These are conditions of influence on the spatial resolution of CR system. The image that have small size of IP or focus, and have proper magnification or condition of exposure can have higher resolution than others.