The Fenghuangshan is a large Cu skarn deposit in the Low—Middle Yangtze metallogenic province. Based on microthermometric and isotopic (C, H, O, S, and Pb) studies, we discuss oreforming fluids evolution and metal origin (s) of the Fenghuangshan Cu deposit. H2O—CO2 type fluid inclusions, which can be classified into liquidrich, vaporrich and daughter crystalbearing subtypes, are ubiquitous in diopside, garnet, quartz and calcite. Laser Raman spectroscopic analysis indicates that liquid phase of fluid inclusions is H2O, and vapor phase is dominant by CO2, N2 and CH4. Homogenization temperature (Th) and salinity of fluid inclusions suggest threestage history of oreforming fluids, reflecting an evolution process from hightemperature and salinity at mineralization stage to lowtemperature and salinity at post mineralization stage. Temperature decreasing and fluids boiling may be responsible for precipitation of large quantity of metals. Hydrogen and oxygen isotope of quartz and calcite indicate that magmatic fliud was dominant during the oreforming stage, whereas a small quantity of meteoric fluid mixed with original magmatic fluid at post oreforming (or late) stage. Narrow variation range of pyrite δ34S (1.8‰~ 2.9‰) suggest that sulfur was from a relatively uniform reservoir, substantially from mantle. Pb206/Pb207 values of oreforming stage pyrite present magmatic hydrothermal characteristics, which further suggest metals of the Fenghuangshan Cu deposit were from mantle.