The Tongyu copper deposit, located in the western part of the North Qinling Orogen, China, is one of several volcanic-hosted massive sulphide(VHMS) deposits with industrial value and is also a typical example of mineralization related to the subduction and metallogenesis during the Caledonian orogeny. We conducted systematic lead-sulphur isotope geochemical analyses of the Tongyu deposit to understand the possible ore-forming material sources and tectonic settings. Twenty-six sulphide samples yielded clustered δ~(34)S_(CDT) values of 1.13‰-3.36‰, average 2.22‰, and show a tower-type distribution,implying that the sulphur of the Tongyu copper deposit mainly originated from a mantle source. The Pb isotope compositions of sulphides(~(206)Pb/~(204)Pb = 17.59225-18.56354, average 18.32020; ~(207)Pb/~(204)Pb =15.51770-15.69381, average 15.66217; ~(208)Pb/~(204)Pb= 37.99969-39.06953, average 38.52722) are close to the values of the volcanic host rocks(~(206)Pb/~(204)Pb= 18.10678-18.26293, average 18.21158; ~(207)Pb/~(204)Pb =15.63196-15.68188, average 15.65345; ~(208)Pb/~(204)Pb= 38.43676-38.56360, average 38.49171), thus consistent with the Pb in ores and volcanic host rocks having been derived from a common source that was island-arc Pb related to oceanic crust subduction. The northward subduction of the Palaeo-Qinling oceanic crust triggered dehydration of the slab, which generated a large amount of high-oxygen-fugacity aqueous hydrothermal fluid. The fluid rose into the mantle wedge, activated and extracted metallogenic material and promoted partial melting of the mantle wedge. The magma and ore-forming fluid welled up and precipitated, finally forming the Tongyu VHMS copper deposit. The Tongyu copper deposit, located in the western part of the North Qinling Orogen, China, one of several volcanic-hosted massive sulphide (VHMS) deposits with industrial value and is also a typical example of mineralization related to the subduction and metallogenesis during the Caledonian orogeny. We conducted systematic lead-sulfur isotope geochemical analyzes of the Tongyu deposit to understand the possible ore-forming material sources and tectonic settings. Twenty-six sulphide samples yielded clustered δ ~ (34) S_ (CDT) values ​​of 1.13 ‰ - 3.36 ‰, average 2.22 ‰, and show a tower-type distribution, implying that the sulfur of the Tongyu copper deposit mainly originated from a mantle source. The Pb isotope compositions of sulphides (~ 206 Pb / 204 Pb = (207) Pb / 204 Pb = 15.51770-15.69381 average 15.66217 208 Pb / 204 Pb = 37.99969-39.06953 average 38.52722) are close to the values of the volcanic host rocks (~ (206) Pb / ~ (204) Pb = 18.10678-18.262 93, average 18.21158; 207 Pb / 204 Pb = 15.63196-15.68188 average 15.65345; 208 Pb / 204 Pb = 38.43676-38.56360 average 38.49171 thus essentially with Pb in ores and volcanic host rocks having been derived from a common source that was island-arc Pb related to oceanic crust subduction. The northward subduction of the Palaeo-Qinling oceanic crust triggered dehydration of the slab, which generates a large amount of high-oxygen- fugacity aqueous hydrothermal fluid. The fluid rose into the mantle wedge, activated and extracted metallogenic material and promoted partial melting of the mantle wedge. The magma and ore-forming fluid welled up and precipitated, finally forming the Tongyu VHMS copper deposit.