Al alloy has been used in several kinds of industries against a background of environmental problem and energy saving .However, Al alloy has poor wear-resistance, so in order to solve this problem, Diamond Like Carbon(DLC) coating which indicates high tribological properties was performed. In this paper, the effect of thin hard coatings on the tribological and fatigue strength of Al alloy was investigated. The coatings were DLC and Aluminum nitride (AlN) with Unbalanced Magnetron Sputtering (UBMS) method. Wear tests and fatigue tests were carried out. Al alloy coated DLC and AlN indicated high fatigue strength compared with Al alloy coated with AlN and substrate only.