The fracture process of Fiber Reinforced Plastics (FRPs) is mainly governed by mesoscopic fracture events, such as fiber breakage, matrix cracking, interfacial debonding and their mechanical interaction.However, it has been very difficult to observe the fracture process of FRPs directly and in detail.This is because FRPs fracture in a moment when the load reaches the critical value.Particularly, the tensile fracture of unidirectional (UD) FRPs shows catastrophic behavior, and its speed sometimes reaches the subsonic region.