The fifteen years' progress in the study of photonic crystals from being proposed to present was surveyed. The conception of photonic crystal and characteristics of inhibited spontaneous emission and localization of photons were described at first, then the research in theory, experiment and application were introduced respectively. The plane-wave expansion method, Green's function method, finite-difference time-domain method and transfer matrix method were described in theory research. In experiment research, fabrication method of photonic crystals was depicted;measurement method on characteristic parameter was depicted also. In application, photonic crystal fibers and waveguide, omnidirectional reflection microcavity, photonic crystal filters, hight extraction efficiency diode, nonlinearity optics effect in photonic crystals were decribed.