Abstract: he theoretical and finite element models were established for the Lshape polymer profile gasassisted extrusion. The computer simulation was carried out with the aid of Polyflow software. The analysis showed that, during the gasassisted extrusion, a gas layer was established in the die and the frictional resistance was greatly reduced. The flow of polymer melt became the same，the die swell could be reduced effectively. So the shape and dimension precision of the extrudate could be improved which was helpful for the polymer extrusion processing with high speed and high quality.

Key words: gas-assisted extrusion, profile, die, extrusion;die swell;computer simulation