Abstract: Birefringent behaviors of some currently used fiber-reinforced sites and transparent filament-resin photoelastic rriaterials were investi gated by using a self-made Laser Optical Microscopic Analyzer(LOMA).The birefringent characteristics were estimated based on a I-O curve recorded,where I is the light intensity transmitted normally through polarizers and a specimen,and O is the pass plane of the polarizer.