The invention relates to a multilayer multi-element composite hard PVD coating with low friction coefficient on the surface of a piston ring, a piston ring and a preparation process. The present invention employs vacuum multi-arc ion plating vapor deposition process, which uses multiple multi-arc ion sources, in the combination of equipping with different single metal target material and multi-element target material to deposit multilayer multi-element composite hard PVD coating with low friction coefficient on the surface of a steel or cast iron piston ring. The coating consists of five layers with the total thickness of up to 60 μm. The coating has high adhesion with the surface of piston ring, high hardness, low friction coefficient and good abrasion resistance. By controlling the adding amount of additive elements Al, Mo, W, B, Si and Ti, the friction coefficient of the coating can be further reduced 5 to 20% compared with that of a single TiN or CrN deposited layer.