Noble gases are widely used as geochemical tracers. In this study, noble gas isotopes of olivine and pyroxene in nephelinites from Wajilitag of Northwest Tarim large igneous province were analyzed. The results show low ³He/⁴He ratios (2.0~2.4 Ra and 0.65~0.85 Ra, respectively) and low ⁴⁰Ar/³⁶Ar ratios (342.3~651.7, slightly higher than atmospheric value). This feature can be interpreted as being influenced by the paleo-subduction. It is inferred that the south Tianshan oceanic plate subducted southward beneath the Tarim plate in the early Paleozoic and the subducting plate brought the fluid enriched with U or ⁴He and atmospheric components into the deep mantle. Furthermore, the nephelinite magma was produced by low degree partial melting of the mantle source region with the involvement of the mantle plume.