Abstract: In order to improve the interfacial strength between Kevlar fibers and composite matrix, LiCl ethanol solution was used to treat Kevlar fibers by certain time. Then, the surface chemical composition, micromorphology, tensile strength of single filament for LiCl treated Kevlar fibers and interface properties of Kevlar fibers/epoxy resin composites etc. were tested and analyzed. The results show that after using LiCl ethanol solution treating Kevlar fibers, the content of nitrogen containing functional groups on Kevlar fiber surface increases. After the treatment, there are some etched grooves appear on the Kevlar fiber surface and the surface roughness increases, thus the adhesion property between Kevlar fibers and epoxy resin matrix enhances, which makes the interlaminar shear strength of Kevlar fibers/epoxy resin composites increases from 21.75 MPa before treatment to 37.98 MPa. The optimum treatment time is 3-4 h, while the unnecessary extend of treatment time will lead to the decrease for the tensile strength of single filament for Kevlar fiber and the interlaminar shear strength of composites. The conclusions obtained proves that using LiCl to treat Kevlar fibers is an effective method for surface modification.