Abstract: The Baergaiti granitoid is located in the Boluohuoluo tectonic belt in the western Tianshan Mountain of the Yili Basin. LA-ICP-MS zircon U-Pb shows age of 374±7.0 Ma, corresponding to the Late Devonian. Petrogeochemical analyses suggest that the intrusion belong to calc-alkaline metaliferous rocks characterized with high silica, potassium, and alkalinity, low magnesium and titanium. The contents of SiO₂, Al₂O₃, K₂O, Na₂O range 70.72%-79.12%, 9.87%-14.51%, 4.13%-5.54%, 2.87%-4.35%, respectively. Meanwhile, the REE contents show an obvious rich LREE pattern ((La/Yb)_N ranges 7.61-16.31) with negative Eu anomalies. Large ion lithophile elements such as Rb, Th and U are relatively enriched, whereas high strength field elements such as Nb, Ta and Ti are relatively depleted. Geochemical and isotope characteristics show a transition feature of high-K calc-alkaline I-A type granite. The analyses of a regional angular unconformity and sedimentary features suggest that the Baergaiti granitoid was deposited under a post-orogenic intra-continental extensional tectonic setting during the Late Devonian, and formed a complete tectonic evolution cycle coupling with the Carboniferous volcanic-sedimentary strata.