Abstract: The prepreg of continuous glass fiber reinforced PP was prepared by using powder impregnation process and cut into the pellets of long fiber reinforced PP. The compression molding process of such long fiber reinforced PP was investigated. The mechanical properties and their influential factors of the products were also studied. It was found that the parts with an excellent mechanical property could be obtained after the powder impregnating long fiber reinforced PP was compression molded. With the increment in the cut length of the prepreg and fiber content, the mechanical property increased. The modification of the interfacial adhesion between glass fiber and PP by using functionalized polypropylene grafted polar group (MPP) played a significant role in improving the mechanical properties of the composites, but the impact strength decreased above a certain level of MPP. The mechanical properties would increase when increasing the molding pressure and the temperature of mould and molding compound during the compression molding processing.