Abstract: The influence of pre-heating on resistance to pushing-away phenomena of Ti-6Al-4V alloy powder in electron beam selective melting process was investigated.Three dimensional parts are formed using Ti-6Al-4V alloy powder to study the effects of pre-heating.Results indicate that pre-heating process can increase the antipushing-away critical scanning speed, and improve the anti-pushingaway capacity of the powder.Meanwhile, pre-heating process can diminish "exterior scar" and "balling" phenomenon, keep the layer thin, and get better fusion between layers.