This study uses simple upsetting processes of copper to investigate the effects of temperature and grain refinement on stress-strain behaviour. The equal channel angular extrusion (ECAE) and heat treatment techniques were applied to refine and control the grain size of copper in a range between 4 m and 46 m. The coppers were then machined to prepare the billets with 2 mm diameter and 3 mm height. To conduct the upsetting processes at elevated temperature, a forming system equipped with a heating device was also developed. The experimental results show that the copper billets with refined grains have higher strength than those with coarse grains prepared by annealing treatments. The grain refinement and the increase in forming temperature can improve material flow behaviors and thus lead to a better edge quality of the deformed workpiece.