Studies of the geology, types and composition of fluid inclusions and stable iso-topic composition show that auriferous quartz veins in the Jinshan shear zone type deposit, Jiangxi Province, was formed by mineralization and superimposition of early-formed barren quartz veins by late-stage native gold when the former were subjected to cataclasis and mylonitization. Native gold superimposition occurred by means of the action of subsurface hydrothermal waters; therefore the factor responsible for the deposition of native gold was mainly the phase separation of ore fluids.