Abstract: The Jinshan gold deposit, occurring in the lower member of Lower Carboniferous Dahalajunshan volcanic clastic formation, is a typical epithermal and large-sized gold deposit in Yining County, Xinjiang. On the basis of detailed field geological survey and systematic laboratory study such as microscope observation, chemical analyses, mineral phase analyses, electron probe scanning, X-ray surface scanning, the occurrence of gold has been determined. The result shows the gold exists mainly as the independent mineral face; the carriers are mainly pyrite, quartz and limonite. The major gold minerals are native gold, the average fineness is from 969.6 to 997.8. The minor argentiferous native gold and electrum are also identified. Gold is embodied as intergranular, inclusion, fissure-filling, and interlocking form. The gold granularity is mainly characterized by micro particulate (0.01~0.005 mm, which accounts for 60%) and extra micro particulate (0.005~0.0002 mm, which accounts for 26.6%). Although the micro medium size and micro fine grained gold is less, however, it is significant to ore grade and total resource.