Abstract: The outcrop of diabase dikes in Halaqi of Xinjiang has provided important information for tectonic evolution of southwest Tianshan area. The diabase dikes in Halaqi area lack HFSE(Nb, Ta)and HREE(Yb, Y), and exhibit enrichment in LILE(Ba, Sr, K) and LREE(La, Ce). With the geochemical characteristics of depleted mantle, it can be understood as the mantle was transformed by subduction in plate subduction, indicating that during the Late Carboniferous-Early Permian, the region should have been in the island arc environment.