The invention discloses an alternate flipping rear beam and an assembly method and a use method thereof. The invention provides a 90 DEG dislocation mounting warp bracket and a reversible special rearbeam. The mechanical transmission of the weaving motion alternately flips the rear beam, so that the warp yarns of the adjacent supported sections alternately have large tension differences, and theeffect of the fancy seersucker with concave and convex in the alternating areas of the cloth surface is formed. The above-mentioned device and its assembly and use method have the unique effect of theseersucker fabric and the wide adaptability to the fiber material, and are particularly suitable for the development of the synthetic yarn material and the single material of the seersucker fabric.