The Maoniuping deposit in Mianning, Sichuan, is one of the most significant rare earth element (REE) deposits, situated within the Mianning-Dechang Himalayan REE metallogenic belt in southwestern China. Previous studies on Homo sapiens have indicated that REE mineralization is closely associated with alkaline-carbonatite complexes in the region, but there remains considerable debate regarding the genesis of these complexes and the timing of REE mineralization. This study obtained ages of 25.31±0.26 Ma (MSWD=4.3, n=12) for alkali-feldspar granite porphyry and 26.0±0.3 Ma (MSWD=2.0, n=15) for alkaline syenite, both of which fall within the error range of the magmatic age of the alkaline-carbonatite complexes in the area. This suggests a genetic link between the alkali-feldspar granite porphyry and the complexes, further supporting the formation of ore-bearing alkaline complexes during the transition from the Paleogene to the Neogene in the Cenozoic era. LA-ICP-MS U-Pb dating of bastn?site from different ore types ages of 32.68±0.66 Ma (n=21) for breccia-type ores, 30.2±0.89 Ma (n=16) and 30.19±0.77 Ma (n=19) for aegirine-augite-type ores, and 27.61±3.43 Ma (n=23) for calcite-type ores. The sequence from breccia-type ores → aegirine-augite-type ores → calcite-type ores → alkaline syenite → alkali granite porphyry shows progressively younger but continuous ages, indicating that mineralization occurred over a span of 6~7 Ma. This process was initiated by tectonic activities, which facilitated the upward migration of ore-bearing, fluid-rich magmas from deep crustal or possibly even mantle depths to shallow subsurface levels, forming subvolcanic rocks (porphyry). The simultaneous interaction of magma and magmatic hydrothermal fluids led to intense fracturing, alteration, and reverse crystallization of ores and rocks. This characteristic also suggests that the REE and F-rich metallogenic melts-fluids were not products of fractional crystallization of alkaline syenite and alkali-feldspar granite porphyry but rather resulted from direct crystallization of magmatic melt-fluids. Therefore, alkaline syenite and alkali-feldspar granite porphyry can serve as prospecting indicators for Maoniuping-type REE deposits. If alkaline syenite and alkali-feldspar granite porphyry were erupted into a marine environment, they might form trachyte or K-rich tuff similar to the H8 unit in the Bayan Obo deposit. In other words, while the Bayan Obo and Maoniuping REE deposits share common metallogenic mechanisms, their mineralization environments are fundamentally distinct.