The invention belongs to the field of metal material processing, in particular relates to an edge controlled rolling method for prefabricating a magnesium alloy slab edge crown by a profiled roller, and aims at solving the problem of edge cracking in the process of rolling a magnesium alloy medium-thick slab with a thickness of 10-30 mm into a thin sheet. A rolled piece is rolled for the first pass by using the profiled roller of which both ends have a certain taper, and then the slab with the prefabricated edge crown is rolled into the magnesium alloy sheet by using a flat roller. After the edge crown is prefabricated by rolling of the profiled roller, the temperature drop in the edge area is slowed down; the subsequent rolling process by the flat roller is beneficial to the refinement ofthe grain size of the edge; and the tension stress of the edge of the deformation area is greatly reduced, and due to compression stress on part of the area, the stress state of the deformation areaduring ordinary flat roller rolling is improved, and the edge damage is reduced. The method can effectively control the edge cracking problem in the magnesium alloy rolling process, improve the yieldof the magnesium alloy sheet, and reduce the production cost.