This article briefly reviews the applications of small angle X-ray scattering (SAXS) and ultra-small angle X-ray scattering (USAXS) in the study of coal pore structure. By analyzing the microscopic pore structures of coal, this study explores the advantages of SAXS and USAXS techniques in revealing the adsorption performance, gas diffusion properties, and conversion of coal. A detailed description of the basic principles, experimental methods, and application examples of these two techniques at synchrotron light sources is provided, demonstrating their irreplaceable role in coal research. Combining the characteristics of coal resources in China, it is pointed out that SAXS and USAXS have broad prospects for application in the cross-scale research of coal.