Abstract: The impact properties of ultra-high molecular weight polyethylene (UHMWPE) fiber/epoxy weft plain knitted composites by vacuum assisted resin transfer molding (VARTM) process were investigated by considering impact energy and absorbtion energy profile diagram and the related contact force–deflection curves. The composites consisting of 4, 6, 8 layers weft plain knitted structure were subjected to different impact energies (10-55 J). The damage modes and damage processes of fabrics under varied impact energies were also discussed. Results show that the maximum contact force is observed in 8 layers weft plain knitted structure, followed by 6 layers weft plain knitted structure, and the minimum contact force is observed in 4 layers weft plain knitted structure; the impact deflection of three knitted composites is increased by increasing the impact energy; the effective damage modes for penetration are matrix cracking and fiber splitting, matrix and fiber breakage is the effective damage mode in the case of perforation.