Using geochemical methods, the authors investigated the provenance of Middle Permian Zhesi Formation sandstone and its tectonic setting in northeast Inner Mongolia. By analyzing major elements, trace elements and rare earth elements, it is found that the sandstone samples are all characterized by high SiO₂, Al₂O₃, Fe₂O₃ and low CaO, MgO, with their values being 67.87%～71.94%, 14.57%～15.61%, 2.61%～6.20%, 0.31%～0.58% and 0.80%～1.93% respectively. The upper crust normalized spider diagrams are characterized by enrichment of LILE such as Ba and Sr and depletion of HFSE except for Zr and Y. The trace element analysis demonstrates the obvious enrichment of LREE relative to HREE, with significant Eu anomalies, (La/Yb)_n=5.08～8.67, Eu/Eu^*=0.56～0.77. The provenance of the Middle Permian Zhesi Formation sandstone in the work area might have been derived from felsic rocks of the upper crust, including granites. The tectonic setting of the provenance of the Middle Permian sandstone in the work area was a continental island arc.