Abstract: Self-lubricating C/Cr composite coatings were prepared by unbalanced magnetron sputtering technology on the substrate surface of single crystal Si and 45 steel. Chemical composition, phase structure, microstructure and self-lubricating performances were investigated by means of X-ray photoelectron spectrometer, X-ray diffraction, scanning electron microscopy, transmission electron microscopy and pin-on-disc friction and wear tester. The results show that phase structure of the coatings was amorphous, mainly consisted of carbon and chromium simple substance and their compounds. Microstructure of the coatings was influenced by the chromium target current, with increasing the current, the coating surface became rough, the particles were more closely and the friction coefficient increased. The coatings had a large number of graphite phases when the chromium target current was 0.1 and 0.3 A, better self-lubricating performance and carrying capacity.