Surface pretreatment is a key process in preparation of high-performance metallization Kevlar fiber. Electroless Cu plating was conducted on a Kevlar fiber using a new pretreatment method called non-etching and Pd-free activation with dimethyl amine-borane as the reducing agent. Chemical compositions, crystal structure and surface morphology of the coatings were investigated using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and scanning electron microscope (SEM). Adhesion strength, mechanical properties and thermal stability of the coatings were evaluated. The results showed that the obtained Cu deposit was continuous and compact, and possessed high adhesion with the Kevlar fiber. The Cu plated Kevlar fiber maintained excellent mechanical properties and thermal stability.