In this article metallic iron in vanadium-slag tread with sodium is separated by abrading and leaching with CuSO4 solution. The residual copper sulfate is scrubed with ammonium citrate, and the quanity of metallic iron is determinated by indirecting electro-weight analysis. Corpper whinh is replaced out during the process can be solved selectedly by NH2OH-H2SO4 Solution, and its result is satisfactory. This method's reliability is proved by returning test, metallogrrphic assay and X-ray diffraction cerification.