The high fractionated high-silica rhyolite is a potential host of the rare earth elements (REE) deposits. The Tarim Large Igneous Province (TLIP) is characterized by a high proportion of felsic rocks, but it is still unclear about the potential capacity of the REE mineralization. In this study, ignimbrite from drill S42 in Northern Tarim Uplift was studied, and several Fe-P-REE enriched mineral assemblages were recognized: (1) the lithoclast consisted of quartz rim and magnetite+monazite+alkali feldspar core; (2) the magnetite+monazite+rutile+apatite in the groundmass; (3) the monazite+pyrite in the quartz phenocryst. Further analysis of quartz SIMS oxygen isotopes in situ showed that the variation range of the δ18OV-SMOW values of lithic quartz range from 11.15 to 14.60‰, while those of the quartz phenocrysts are from 7.23 to 7.84‰, consistent with the bulk-rock oxygenic composition (5~7.21‰). A titanium thermometer of quartz shows that the formation temperature of quartz phenocryst was 756~815℃, and that of the lithic quartz was 566~645℃. In addition, trace elemental composition of magnetite that is associated with quartz in the lithoclast also show they are consistent with those of the hydrothermal origin. The above evidence indicates that the Fe-P-REE mineral assemblage in the lithoclast was derived from the late hydrothermal fluids. On the other hand, the occurrence of Fe-P-REE mineral aggregates in the groundmass of the ignimbrite and quartz phenocryst indicates that the magma has been sufficiently enriched in REE and then crystallized REE minerals in the late stage of evolution. Therefore, the Fe-P-REE enriched mineral aggregates in the ignimbrite are mainly related to the magmatic fractional crystallization and the late hydrothermal fluids. The recognition provides an important implication for the REE mineralization of the felsic rocks in the Tarim igneous province.