In order to investigate the temperature rise of the workpiece during equal channel angular pressing (ECAP), a lumped heat transfer analysis was made. The main deforming zone was taken as the analysis domain. The temperature rise due to the work of plastic deformation and the frictional heat was considered. An equation for the temperature rise during the ECAP process was derived. The temperature increment increases with the strength of the material, the ram speed and the channel angle, and decreases as the density, the heat capacity and the die corner angle increase. The model was applied to Al and Al alloys with different ultimate tensile strengths. The calculated temperature rise is in good agreement with published experimental results.