The coming out of photonic crystal fibers makes the research of polarization maintained photonic crystal fibers become a hotspot in the field of optical communication. Based on summarizing large numbers of research documents about PM-PCFs in domestic and aboard,the light propagation mechanism and polarization maintaining principles of high birefringence PM-PCFs are analyzed. Furthermore,various design schemes are presented. Finally,the present progress,applications,and foreground of development are put forward.