Abstract Fluid inclusions provide information on the genesis of mineral deposits and can be used in mineral exploration. A hidden orebody at the Sangdong tungsten ore deposit was found by fluid inclusion study. Maximum homogenization temperature values obtained from quartz in skarn at Sangdong delineated the main channel of ore fluid, as well as branch of the channel related to a hidden skarn orebody. High homogenization temperatures ( T h ) obtained from fluid inclusions in pyroxene and garnet suggested the presence of a granitoid heat source near the skarn orebody, which was proved by discovering the Sangdong Granite.