A slide rail assembly, configured to mount a carried object to a rack, the rack comprising a first post and a second post, and adapted to different distances between the first post and the second post, the slide rail assembly comprising: a first rail comprising an upper wall, a lower wall, and a longitudinal wall connected between the upper wall and the lower wall; a second rail longitudinally movable relative to the first rail, the carried object being configured to be mounted on the second rail; a third rail movably connected between the first rail and the second rail; a reinforcing member attached to a first portion of the first rail, the reinforcing member comprising an upper wall, a lower wall, and a middle wall connected between the upper wall and the lower wall of the reinforcing member, the middle wall of the reinforcing member corresponding to the longitudinal wall of the first rail, and the upper wall and the lower wall of the reinforcing member corresponding to the upper wall and the lower wall of the first rail respectively; a first bracket slidably connected to the reinforcing member and configured to be mounted to the first post, the first bracket comprising an upper wall, a lower wall, and a middle wall connected between the upper wall and the lower wall of the first bracket, the middle wall of the first bracket corresponding to the middle wall of the reinforcing member, and the upper wall and the lower wall of the first bracket corresponding to the upper wall and the lower wall of the reinforcing member respectively; and a second bracket attached to a second portion of the first rail and configured to be mounted to the second post; characterized in that the upper wall and the lower wall of the first bracket extend with bending portions (70a, 70b) respectively facing side portions (64a, 64b) of the upper wall and the lower wall of the reinforcing member. a first rail comprising an upper wall, a lower wall, and a longitudinal wall connected between the upper wall and the lower wall; a second rail longitudinally movable relative to the first rail, the carried object being configured to be mounted on the second rail; a third rail movably connected between the first rail and the second rail; a reinforcing member attached to a first portion of the first rail, the reinforcing member comprising an upper wall, a lower wall, and a middle wall connected between the upper wall and the lower wall of the reinforcing member, the middle wall of the reinforcing member corresponding to the longitudinal wall of the first rail, and the upper wall and the lower wall of the reinforcing member corresponding to the upper wall and the lower wall of the first rail respectively; a first bracket slidably connected to the reinforcing member and configured to be mounted to the first post, the first bracket comprising an upper wall, a lower wall, and a middle wall connected between the upper wall and the lower wall of the first bracket, the middle wall of the first bracket corresponding to the middle wall of the reinforcing member, and the upper wall and the lower wall of the first bracket corresponding to the upper wall and the lower wall of the reinforcing member respectively; and a second bracket attached to a second portion of the first rail and configured to be mounted to the second post; characterized in that the upper wall and the lower wall of the first bracket extend with bending portions (70a, 70b) respectively facing side portions (64a, 64b) of the upper wall and the lower wall of the reinforcing member.