Abstract: In this paper iTis proposed to measure the change of viscosity of composite resin using fiber optic microbend attenuation. Proper optical fibers were selected and processed to increase sensitivities. Experiments of viscosity measurement for different lay up conditions were accomplished and the results were compared to dielectric measurement. ITis found that fiber optic attenuation is sensitive to composite cure monitoring in autoclave with good reliability which can indicate the gel point and the end point of the cure processing. The sensitivity is found to be related to the cross angle of optical fiber to reinforced fiber and the pressure in cure process. Embedded optical fibers which can accomplish cure monitoring and maintain optical wave guide performance are developed to be two sorts of vibration sensors based on the statistic mode of fiber optic vibration sensing mechanism.