Because tailings of Jinchuan nickel mine are of large quantities and contain considerable valuable metals, the recovery of valuable metals from them have aroused more and more attention. Investigations reveal that the modes of occurrence of Ni and Cu are complicated in old flotation tailings, and they occur in different amounts in all the phases of water soluble fraction, exchangeable fraction, carbonate fraction, poorly crystalline Fe oxide fraction, good crystalline Fe oxide fraction, sulfide fraction and silicate fraction. The metal ions released from metal sulfide oxidation are mainly precipitated and adsorbed in situ and not concentrated in tailings. The acid leaching is more appropriate for the recovery of Ni and Cu from the flotation tailings of Jinchuan nickel mine.