Abstract: The Qinglong antimony deposit in southwestern Guizhou is an important Sb-producer in South China．Despite previous detailed investigations，no agreement has been reached on the source of ore-forming materials．Sr isotope ratios of fluorites from the Qinglong antimony deposit are in the range of 0.70776 to 0.70932．These are significantly higher than Sr isotope ratios for host sedimentary an d igneous rocks of 0.70672 to 0.70821 for the Permian Maokou limestone and of 0.70441～0.70638 for the Emeishan basalt, respectively．It appears that the ore-forming fluid is relatively enriched in radiogenic 87Sr, suggesting an exterior origin(probably deeper sedimentaly or basement rocks)rather than the country rocks, and an open system of Sb-F mineralization．Because the Sr isotope ratios of the ore-forming fluid ale significaly higher than those of the Emeishan basalt，it is not appropriate to ascribe the Sb-F mineralization in Qinglong deposit to magmatic-hydrothermal process associated with the basaltic eruption．The Sr isotope ratios of the fluorites are also higher than those of the Permian limestone an d coeval seawater，so it is impossible that the ore-forming fluid could be derived only from the Permian seawater．Consequently a genetic model of submarine volcanic sedex is also not suitable for this antimony deposit．This conclusion coincides with our previous result deduced from REE geochemistry ． Existing hydrogen and oxygen isotope studies of ore-forming fluid indicate an origin of highly evolved meteroric water (by reaction with host rocks) rather than seawater．Considering that the ore-forming fluid and the metallogenic materials such as F an d Sb were not simply derived from the host rocks，the Sb-F mi neralization at Qinglong district was not resulted from in-situ remohilization as expected ．