Abstract: The continuous glass fiber/polypropylene (GF/PP) composites were prepared by thermoplastic pultrusion using GF/PP commingled yarns. The effect of mold temperature and pulling speed on the centraline temperature of GF/PP composites was studied. Based on Fourier law, the transient heat transfer within mold cavity in pultrusion process was analyzed. The process parameter matrix was established. The centraline temperature variation of GF/PP composites under the conditions of different mold temperatures and pulling speeds was predicted using finite element numerical calculation. The combination of process parameter for certain mold structure was optimized. The flexural modulus of PP/GF composites obtained at different temperatures and pulling speeds was tested and the sections were observed. The results show that the pultrusion speed should not exceed 350 mm/min, while the mold melt zone temperature should be set higher than 180℃ in the pultrusion process of GF/PP commingled yarns; the optimized process parameter for best mechanical properties of GF/PP composites is obtained at 150℃-230℃-50℃ temperature and 100 mm/min pulling speed. The pultrusion speed is more important than the mold melt zone temperature in pultrusion process of GF/PP commingled yarns.