Abstract: The discovery of single crystal X-ray diffraction in 1912 not only marks the birth of modern crystallography, but also has a profound impact on the development of physics and many other related fields. X-ray powder diffraction extends the structure analysis method to common polycrystalline materials, and then becomes one of the most important characterization means being widely used in physics, chemistry, and materials science in particular. Here we demonstrate the applications of X-ray powder diffraction in exploring new functional materials based on some typical works on new borates and iron-based superconductors in our group. With the emerging and development of new methods and technologies, we believe that X-ray powder diffraction will play a more important role in the exploration of new materials and other related fields.