Abstract: The continuous glass fiber reinforced polypropylene (GF/PP) prepreg was prepared by melt impregnation method. The rheological measurements show that PP behaves Carreau fluid characteristics. Based on the Darcy's law, an impregnation model of Carreau fluid impregnating continuous GF bundle was proposed, taking the structural parameters, material properties and process parameters into account. The impregnation model was validated after experiments under different impregnation temperatures and pulling speeds, and the experimental results agree with the theoretical values. The impregnation procedure was analyzed by utilizing the model, and the results show that the impregnation degree can be raised significantly through increasing the dipping rolls number and radius, reducing the spacing between the rollers, and increasing the impregnation temperature.