Ti-doped DLC films were synthesized from C2H2 and Ti by ion beam deposition and magnetron sputtering, and the influence of Ti target current on the structures and the friction coefficients of Ti-doped DLC films were studied by SEM, AES, XPS, a ball-on-disk friction tester. The Ti content in Ti-doped DLC films is below 1at% when Ti target currents rise up to 3.5 A; but when Ti target current exceeds 3.5 A, Ti content in the films is obviously increased with increasing Ti target current. Ti-doped DLC films have a smooth dense surface with several particles dispersed in it and the surface morphology deposited with different Ti target currents is similar. With the augment of Ti target current, the ratio of sp3-C to sp2-C is almost a constant first, and then an obvious rise followed by an abrupt decrease is found; but only when Ti target current is above 5A, the ratio of TiC-C to sp2-C is obviously increased with Ti target current. The lowest friction coefficients are obtained for the Ti-doped DLC films with the highest ratio of sp3-C to sp2-C and a low ratio of TiC-C to sp2-C.