A slide rail includes an inner slide, an intermediate slide, a rack and a positioning element. The intermediate slide is used for receiving the inner slide; a block is positioned at an end of the intermediate slide. The rack has a plurality of ball bearings. An end of the rack is resisted against the block. The positioning element includes a fixing portion mounted to the intermediate slide, and a resilient hook portion having an ear part, the ear part capable of resisting against the other end of the rack to locate the rack.