Abstract: Using Polyflow software，numerical simulation was implemented for inverse design with three kinds of extrusion die. The die lip shape of T-shape，velocity field，pressure field was obtained. The simulation displayed that the die lip shape of T-shape was unrelated to shape of transition section. The widened transition section was beneficial to balance the outlet velocity and extrusion pressure.

Key words: inverse numerical simulation, T-shape die, finite element method, plastics profile