The impeller is an important component applied in airplanes, ships and weapons. It is difficult to form the complicated geometry of the impeller by using the conventional forging and casting technology. Semi-solid forming is a promising forming process that can produce complicated and high-quality components of wrought aluminum alloys. In this paper, the formability of the impeller was investigated by using advanced semi-solid forming technology and self-designed combined die, as well as quick forging hydraulic press. Experimental results show that the formability of the impeller increases with the increase of reheating temperature and holding time of the billet. When heating temperature and holding time during the pretreatment of the billet were 620°C and 25 min respectively, reheating temperature and holding time of the billet before thixoforging were 600°C and 90 min respectively, preheating temperature of the die was 320°C , the impeller was formed perfectly on the quick forging hydraulic press.