Abstract: The Xinliaodong copper-polymetallic deposit of Eastern Guangdong Province is one of newly discovered deposits. The ore district belongs to tin, tungsten, and copper ore cluster in the southeast coast, which have a very good ore-forming geological conditions. Chalcopyrite has δ⁶⁵Cu value ranging from-0.34‰ to +1.37‰, which is consistent with δ⁶⁵Cu value of porphyry deposits, indicating that ore-forming material Cu was derived from deep magma and ore-forming fluids were medium-high-temperature (250-420℃) magmatic-hydrothermal fluids. There is a close relationship between the fractionation of Cu isotope and magmatic hydrothermal activity. The formation of ore body is related to the dissolution of ore-forming fluids. With the increase of depth, there is atrend of increasing δ⁶⁵Cu value, indicating a potential of a largee orebody. Copper isotope can directly indicate the location of the heat source. The δ⁶⁵Cu values are below 0 for copper ore bodies close to the hydrothermal quartz veins.But the copper isotope values are higher in the hydrothermal contact zone, special ore-bearing surrounding rock and tectonic zone where indicates the edge or the front of the main ore body, most obvious ore prospecting mark.