Abstract: The Quruqtagh is located at the junction part between Tarim Craton and Southern Tianshan tectonic zone. The gabbro dike has been found in the western section of Quruqtagh area, which is composed mainly of gabbro. Zircon LA-ICP-MS U-Pb dating yields an age of (411±5)Ma, implying that the magmatic crystallization epoch of the gabbro is lower Devonian. Geochemical characteristics show that SiO₂ contents range from 48.60% to 50.61%, while MgO contents range from 5.51% to 7.96% with Mg^# values of 51~59. This gabbro is characterized by calk-alkaline basaltic series, with relative LREE enrichment and weakly Eu anomaly in the chondrite-normalized REE patterns. In the primitive mantle-normalized trace elements patterns, this gabbro is enriched in LILEs such as K and Rb, while it's depleted in HFSEs, such as Nb, Ta, P and Ti. According to the comprehensive synthesis on regional geology and geochemical characteristics, the gabbro magma is considered to have been derived from partial melting of depleted mantle wedge that previously metasomatized by slab-derived aqueous fluids. This contribution provides helpful information for understanding the middle Paleozoic tectonic features of southern margin of south Tianshan served as an active continental margin.