Abstract: In order to adopt photonic crystal fibers broadly in the passive devices such as fiber press sensors,the stress of photonic crystal fiber cores and cladding,the transversal structure and the refractive index were theoretically analyzed and simulated by means of elastic-optical theory,and the effect of pressure on the pulse phase and mode birefringence in photonic crystal fibers were discussed.The pulse phase fluctuation and mode birefringence variation in photonic crystal fibers were measured by means of coherent interference technology,and the pressure in the photonic crystal fibers was calculated.It is indicated that the photonic crystal fibers might be used as sensitive elements in the fiber press sensors.It is help that the photomic crystal fibers is more application in the fiber press sensors by this result.