Abstract: The stress distrution of multilayer flat container for extruding aluminum sheet with flange has been simulated by FEM under different heating condition and shrink-fitting range. The results show that the distribution of equivalent combined stress for multilayer flat container with hole size 850×250mm differs sharply between the container with middle heating ring and tha with no middle heating ring. In the stae of hot extrusion under extrusion pressure 500 MPa, the container of shrink-fitting range(2-2,2.0,1.5) can meet the strength condition of the container Whether with the heating ring or not.