Abstract: This article focuses on the FEM software-based simulation of the cage forming process of the medium-sized Φ508 mm×16.13 mm J55 heavy-wall HFW casing,with which the deformation of the strip is studied in the perspective of forming outlook and equivalent plastic strain,and the consistency of the cage forming operation for the said casing is analyzed.The simulation result indicates the facts,namely,generally-satisfactory strip formation,deformation of the equivalent plastic strain up to the manufacture requirement,partial irregular deformation found at the strip end section after the finish forming step,existence of the non-deformation area which runs out from the position about 100 mm from the strip end,and very excellent deformational cross-section.