Abstract: Based on ex-situ toughening concept, the polyamide nonwoven fabric(PNF) with high porosity was chosen as structural toughening layer, and the U3160 carbon fiber reinforced epoxy 3266 composites toughened by interlaminar PNF(U3160-PNF/3266) was fabricated via RTM process. The properties of U3160-PNF/3266 composite were investigated as well as toughening mechanism. The results indicate that the PNF still keep original structure in composites interlaminar, and formed a unreactional co-continuous structure with based resin which show remarkable toughening effect. Mode Ⅰ fracture toughness (G_{Ⅰ C}) and mode Ⅱ fracture toughness (G_{Ⅱ C}) of the U3160-PNF/3266 composites are 1.1 times and 1.4 times higher respectively than that of the control system, and the compression after impact (CAI) increase from 212 MPa to 281 MPa.