The study carried out geochemical analysis of pillow basalts in the group of Qijiaojing, Eastern Bogda Orogenic Belt in East Tianshan. The results show that the basalt belongs to subalkaline tholeiitic basalts, with slight enrichment in LREE ((La/Yb)N=189~221) and a weak Eu anomaly (δEu=089~096), presenting the typical features of islandarc basalts which have negative anomalies of Nb, Ta and Ti. The trace elements of pillow basalts, except active elements (Cs, Rb and Ba), are similar to that of lower crust, between one time to two times contrast NMORB. （La/Nb）N=182~ 262>>1 suggests that the volcanic rocks was contaminated by the lithosphere during the uprising process of magma. Zr content (>142×10-6) and Zr/Y ratio (>4) show the characters of intraplate volcanic rocks. In multiple environment discrimination diagrams, the samples of the volcanic rocks fall into the NMORB area or the margin of IAT area or the intraplate basalt area, presenting characteristics of both NMORB and IAT. Combined with the sedimentary tectonic environment of earlyCarboniferous strata in the region, it can be concluded that the southern Xialaoba area in the Eastern Bogda Orogenic Belt should be in the extension tectonic environment (arcback extension) in the Carboniferous.