Photonic crystals (PCs) are the ordered structures formed by materials with different refractive indices arranged periodically in space. Since the structural unit size matches the wavelength of visible light, PCs have special regulation functions on the light and can block the propagation of specific frequency (wavelength) light in specific directions to form the photonic band gap. This chapter focuses on the research progress of photonic crystal materials, including the preparation technology of polymer microspheres, the processing technology of photonic crystals, and their potential applications in sensing, anti-counterfeiting, display fields and so on.