The invention discloses a method for rolling an iron-based high temperature alloy rectangular ring blank to form a special-shaped thin wall ring piece. In order to enable the rolling process to be continuously and stably conducted, a reasonable feeding mode of a core roller is proposed, the iron-based high temperature alloy rectangular ring blank is designed in a backstepping mode according to the shape and the size of the iron-based high temperature alloy special-shaped thin wall ring piece, and thus the iron-based high temperature alloy rectangular ring blank is rolled to form the special-shaped thin wall ring piece. The method for rolling the iron-based high temperature alloy rectangular ring blank to form the special-shaped thin wall ring piece is mainly applied to forming of iron-based high temperature alloy special-shaped thin wall ring pieces in the fields of aviation, aerospace, industrial machinery and the like.