Photonic crystal fibers(PCFs), have been the focus of increasing scientific and technological interest of optics and optoelectronics, due to their unique and promising properties. The history of photonic crystal fiber is reviewed briefly. The conceptual progress in photonic crystal fiber optics is reviewed. The classification and manufacturing method are introduced. The basic properties of endlessly single mode transmission, manageable dispersion, large mode area, high birefringence, high nonlinearity and potential applications in the nonlinear optics, fiber lasers and other areas are discussed in detail. Their promising future is presented.