Using the injection molding method, impact-resistant polypropylene (PP) and glass fibers (GF) with weight ratios of 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt% and 30 wt% were blended twice, completing high-impact PP/ GF composites. Next, the tensile strength test, flexural stress test and IZOD impact strength test measured the composites. According to the results, with an increase in glass fibers, the composites exhibited a greater tensile strength, which further reached to climax when the GF weight ratio was 25 wt%. However, tensile strength appeared inversely proportionate to the blending frequency. In addition, regardless of blending frequencies, the optimum flexural stress occurred when the GF weight ratio was 25 wt%; nevertheless, it started declining when the ratio was 30 wt%. Finally, indicated by IZOD impact test, the greater the GF weight ratio, the lower the impact strength the composites exited.