The fiber pre-spreading is of great importance when the continuous fiber-reinforced thermoplastic composites are produced by the melt impregnation process. In this paper, an improved spreading device is introduced, in which via grooving the pins for the airflow, the fiber is pre-spread by the combination of the airflow and the rolls. The objective of this operation is to reduce the contact friction between the fiber bundle and the pins surface, thereby reducing fiber fracture during the pre-spreading process. The influence of airflow on the pre-spreading of the fiber bundle is also investigated in this paper. It is found that the effect of airflow on the impregnation is significant and the fiber fracture rate is reduced effectively by analyzing the water absorption rate, interlayer shear strength and fiber fracture rate of the prepreg. When the air pressure is 0.2 MPa, the performance of the prepreg is optimal.