The Qingshan tungsten—tin deposit is a quartz-vein type ore deposit in the Jiulongnao tungsten—tin orefield.The study of Keshuling granites in this deposit not only helps to understand the features of metallogenic geological body,but also can provide evidences for the Indosinian mineralization.Methods: Detail geological survey,LA-ICP-MS zircon U-Pb dating of medium—fine two-mica granite,whole rock geochemical of biotite granite and two-mica granite in Qingshan deposit.Results:The zircon U-Pb dating of Keshuling granite yields emplacement age of 231.0±0.63 Ma (MSDW=0.77),belongs to the product of Indosinian magmatic activities.The whole-rock geochemical analyses show that Keshuling granite has the features of peraluminous,high-K and calc-alkali category,integrated with enrichments of SiO2,Al2O3,K2O,W, Sn,LREE,depletions of MgO,P2O5,TiO2,Sr,Ba,Ti,REE and Eu negative anomaly.Qingshan deposit is rich in tin mine and the orebody can divided into the thin—wide mix vein( upper part) and wide vein (middle and lower part), and little thin—huge vein in granite body. Conclusions: Keshuling granite is formed in the middle Triassic(228~233 Ma).According to the geochemical characteristics,Keshuling granite were mainly formethed by parital melting of crustal sedimentary rocks in the post-collision period or late stage of syn-orogenic tectonic setting.Qingshan deposit is characterized by "two levels" without "basement" of quartz-vein orebodies, and significant rich in tin.Acknowledgements: This research was supported by the geological survey projects by the China Geological Survey(Nos.DD20190166-12 and DD20190166-2020-08).