The Dagangou granites in the Jinshuikou area of the East Kunlun orogen are mainly composed of medium-coarse grained syenogranites. Their SiO₂ and Al₂O₃ values vary from 68.68% to 71.12% and 14.01% to 15.40%, with a mean value of 69.84% and 14.82%, respectively. The K₂O/Na₂O ratios are high (1.19~1.64, with a mean value of 1.40). The A/CNK values[molar ratio of Al₂O₃/(CaO+Na₂O+K₂O)] are 0.98~1.02, with a mean value of 1.00, indicating the quasi aluminum-weakly peraluminous geochemical characteristics. All the Dagangou granites have high total REE abundances. Moreover, their chondrite-normalized REE patterns all show enrichment of LREE and obviously negative Eu anomalies. On the primitive mantle-normalized trace element diagrams, the samples have similar distribution patterns with enrichment of U, Th, and depletion of HFSEs (Ti, P, Nb, Ta) and Ba, Sr, indicating the geochemical characteristics of A-type granite. The εNd(t) values of -5.6~-7.3 and t_DM values from 1.54 Ga to 2.27 Ga suggest that the source might have mainly been derived Proterozoic materials (Jinshuikou Group). Zircon εHf(t)=2.2~2.6, significantly different from the earth's crust magmatic Hf isotopic compositions, showing that rocks were contaminated by the mantle. The LA-ICP-MS zircon U-Pb indicates that the granites were emplaced at 392±2 Ma (MSWD=1.14). The geochemical characteristics combined with the tectonic evolution of East Kunlun show a pronounced affinity of post-orogenic granites, belonging to the response to the mantle magma upwelling and melting of the crust.