The large area of the eastern section of the North Dabei Mountain lies in North Qinling orogenic belt with extensive exposed trachyte, which was formed in early Silurian, sandwiched in lower level carbonaceous silty slates of the Early Silurian Meiziya Group (S₁m) and spread from northwest to southeast. This trachyte is closely related to niobium mineralization. The Tianbao Nb deposit occurs in the middle to lower part of the volcanic sedimentary rhythm. The most important host rock is ignimbrite. The trachytes are alkali-rich, with high ∑REE and enriched LREE. High field strength elements such as Nb, Ta, Zr and Hf are enriched and Sr, P, and Ti are depleted, showing the characteristics of OIB. These characteristics of the trachytes indicate that trachyte magma originated from the evolution of mantle-derived basaltic magma. They are low pressure type trachytes formed in an intraplate rift tectonic environment. Compared with the barren trachyte, the ore-forming trachyte has lower SiO₂, higher Al₂O₃, K₂O, CaO, lower P₂O₅, higher high field strength elements(Nb, Ta, Zr, Hf)and light rare earth elements(La,Ce), stronger negative Eu anomalies, positive Ce anomalies, slightly strongly depleted in P and Ti, and higher volatiles(F, CO₂). Niobium-containing mineral is aeschynite, which was generated along the early mineral edge, cracks or late veins. The metallogenic stage was in the late stage of magmatsim. The enrichment process of element Nb was closely related to the migration and preservation of the volatiles (F, CO₂ etc.). This Nb deposit is a volcanic rare metal deposit, with the characteristics of magmatic type and magmatic hydrothermal deposits. The deposit type is different from that of Miaoya and Shaxiongdong rare earth deposits; nevertheless, they belong to the same mineralization series.