A slide rail assembly includes a supporting frame, a first rail, a second rail and a third rail. The first rail is movable relative to the supporting frame. The second rail is movable relative to the first rail. The third rail is movable relative to the second rail, and the second rail is movably mounted between the first rail and the third rail. The first rail can be moved to a second predetermined position from a first predetermined position in a retracting direction relative the supporting frame. The first rail can be retained at the second predetermined position so as to shorten a length of the slide rail assembly such that the third rail can be detached from the second rail easily in a limited environment.