The invention relates to an anti-slipping supporting rail assembly which comprises a first rail, a second rail, a snapping piece and an elastic piece. The first rail comprises a blocking wall; the second rail is hung on the first rail for sliding and provided with a sliding groove; the snapping piece is connected with the second rail in a pivoting mode and provided with a first end and a second end, and the first end of the snapping piece is provided with a blocking portion; and the elastic piece is arranged between the second end of the snapping piece and the second rail to provide an elastic force for acting on the snapping piece, the blocking portion of the first end of the snapping piece extends into the sliding groove of the second rail by means of the elastic force of the elastic piece, the blocking portion longitudinally corresponds to the blocking wall of the first rail, and the second rail abuts against the blocking wall of the first rail by means of the blocking portion of the snapping piece to form a positioning blocking point when the second rail extends out to slide to a preset position relative to the first rail.