Abstract: Though the homemade impregnation mold, the effects of processing parameters such as roving pulling speed, melt temperature and number of pins on fiber fracture of continuous glass fiber reinforced thermalplastic composites were studied quantitatively in compound process. A fiber fracture mathematical model was developed for producing prepreg process to predict the fiber fracture rate and describe the experimental results. The results suggest that the model and experimental data are in good agreement. The model can provide guidance and reference for industrial production. The fiber fracture is mainly caused by viscous shear effect on fiber bundle when pulling the fiber bundle. Reducing the number of impregnation pins and using low-viscosity resin can significantly ease the fiber fracture, as well aspromote the process stability.