The development of synchrotron radiation science has been extremely useful for the elucidation of unknown properties of polymer materials. Popular features are the shortening of measurement time and the enabling of a high signal-to-noise ratio for very small amounts of sample. In this chapter, advanced research examples of polymer materials using X-ray scattering and absorption methods are introduced. In situ internal structure analyses under various deformation processes, including uniaxial, biaxial, and bulge deformations, of amorphous and crystalline polymer solids and elastomers were performed using wide-angle and small-angle X-ray scattering and X-ray absorption fine structure analysis. Glancing incident X-ray scattering measurement was used to clarify the microphase-separated structure and crystalline one of the thin and ultrathin films with a nanometer thickness. Furthermore, measurement using synchrotron radiation X-ray can perform not only structure analyses but dynamics and mechanical properties of polymer materials by combining rapid measurement and synchronized external field. The results obtained by X-ray photon correlation spectroscopy and dynamic X-ray diffraction measurements applied for a colloidal crystal polymer film and crystalline film, respectively, were provided.