Regarding host rocks and magmatic rocks as a whole system connected by ore fluid activity, the authors systematically investigated the REE behaviors of magmatic rocks, host-rocks and skarns influenced by ore-bearing fluid in the Handagai skarn-type Fe-Cu mineralization area. The REE compositions of Fe-Cu ores imply that they were derived from the contact metasomatism and the ore-forming hydrothermal fluid had relatively high temperature. The authors infer that the ore fluids should be characterized by ∑REE depletion and relative enrichment of ∑HREE and Ce. Results of the study indicate that the application of REE geochemistry to mineral prospecting has great potential.