Abstract: In order to resolve the support problem of large-span roadway, the rectangular roadway is equated to a flat ellipse based on the existing bolting theories. The article studied the stress distribution laws of the surrounding rock of rectangular roadway after analyzing the plastic zone of ellipse roadway by applying the theory of elastic-plastic limited equilibrium, then the article determined anchor (cable) supporting parameters. With the FLAC^3D numerical simulation, the anchor (cable) support of large-span roadway based on equivalent ellipse method could obviously improve the support strength and effect.