Extrusion is a very common process in the plastic production industry. Accurate extruder barrel temperature control has proved to be essential as it is closely related to the final product quality. However, it is widely understood that the process, although very straightforward, imposes a lot of difficulties in control. This paper begins with a general introduction to the modelling of an extruder using SIMULINK Then the paper will proceed to discuss the fundamental difficulties in extruder temperature control The particular problem of Stop-Start events will be highlighted. Finally, a strategy based upon the scheduling of the set-point is proposed. Simulation studies show that both settling time and temperature deviations caused by the change of screw speed can be reduced using this strategy.