Since Prusiner, suggested the prion hypothesis in 1982, a wealth of experiments have supported it to be true. However, the function of the cellular prion protein(PrP^C) remains unclear. But recently evidence is showing that PrP^C could specifically bind to Cu²⁺ and may transport Cu²⁺ to SOD1 by endocytosis from the plasma membrane via clathrin-coated pits so that taking part in copper metablism. Moreover, other evidence also shows that Cu²⁺ could enhance the reversibility of denatured PrP^Sc and may determine the difference of some PrP^Sc strains.