LOTTE CHEMICAL has successfully developed the high performance composites by using PP impregnated continuous carbon and glass fiber. These thermoplastic composites are mainly used in automobile components such as bumper beam, seat back frame, front end module, etc. When the thermoplastic composites are used, the largest benefit is easy recycling automotive parts. Because the car are produced about 80 million per year in world, when 1 kg of thermosetting material is just applied to automobile parts 80,000 ton of non-recycled wastes can come out. In these respects, thermoplastic composites material must be developed more actively than before. Generally as compared with thermoset composites such as carbon fiber/epoxy or glass fiber/epoxy, mechanical properties of thermoplastic composites are lower. In order to improve mechanical properties in carbon fiber or glass fiber reinforced thermoplastic composite, it is very important to minimize the defect at the interface between the fibers and the surrounding polymer. We have developed a manufacturing technology to coat the polymer on continuous glass and carbon fibers by using special die. Additionally, in order to improve the interfacial adhesion between polypropylene and glass or carbon fibers, we have developed and applied adhesive materials. To control the balance of directional the mechanical properties, we have woven continuous glass and carbon fiber composites that have passed through the impregnation process to improve interfacial adhesion. In consideration the clamping force between the warp composites and the weft composites, the space of the weft and warp composites is controlled. These woven composites are used in insert core material in the injection molding process and only structural material in the compression molding process. Keywords: Polymer composites, Thermoplastic composites, Impregnation process, Woven composites.