Ultrahigh pure copper ingot preparing process

The invention discloses a preparation method of ultrahigh pure copper casting ingot, relating to vacuum metallurgy technical field. The invention uses supper pure graphite as crucible pot and die material; the technology process is that the ultrahigh pure copper casting ingot is obtained after the raw material is washed, dried, loaded, vacuum pumped, vacuum melted and vacuum poured; through strictly controlling on each link that may cause pollution before smelting and in the process of smelting and casting, finally the purity of the casting ingot can reach 99.9999 percent and the impurity amount of the metal is less than 1ppm. The invention has the advantages that the casting ingot with large cross section can be manufactured with small investment, low production cost and short production period.