The invention relates to a multi-connecting-rod swinging material-scattering system for a bar straightening machine, which comprises a first rod. The first rod is fixed on a base; the first rod is connected to a second rod through a first node; the second rod is connected to a third rod through a second node; the third rod is connected to a fourth rod through a third node; the fourth rod is connected to an oil cylinder rod through a fourth node; a seventh node in the middle of the fourth rod is fixedly hinged with the base; an oil cylinder is fixedly hinged with the base at a sixth node; the first, second, third and fourth nodes are moveable hinging nodes; the seventh and sixth nodes are fixed hinging nodes; the seventh node is located on the fourth rod; the fourth rod can rotate around the seventh node; the second rod is horizontally arranged and is lower than a rack for placing bent bars; with the help of the motion of the oil cylinder rod, the swinging inclination of the second rod is realized; and the bundled bent bars placed on the rack are scattered, thereby realizing automatic material-scattering. The multi-connecting-rod swinging material-scattering system has the advantages of high efficiency and small labor intensity.