The rare mental niobium- tantalum has multi- epoch metallogenic characteristics in South of China, and the Late Cretaceous metallogenic event as the latest metallogenic stage is rarely reported by predecessors. This paper focuses on the Wuxiaoyang Niobium deposit in southeast of Zhejiang Province. By combining field investigation, petrology, in situ microzone analysis of minerals and isotopic chronology, we determined that the main body of niobium mineralization is fine- grained biotite granite. The diagenetic and metallogenic ages are 89. 2±0. 8 Ma and 86. 5±1. 0 Ma respectively, revealing an important Late Cretaceous granite emplacement and niobium mineralization event in this area. Niobium occurs in the form of independent minerals in columbite group mineral, rutile and plumbopyrchlore. In addition, part of niobium occurs in biotite. Under magma- hydrothermal interaction, the mica evolved from annite to protolithionite to zinnwaldite; the highest Nb- content of annite was 1253×10-6, and the highest Nb- content of protolithionite and zinnwaldite was 794×10-6. As the extremely Nb- rich characteristics of biotite indicate that the deposit has a very well niobium prospecting potential, the Nb- rich biotite can be used as an indicator mineral for niobium- tantalum prospecting. Based on the above mineralogical characteristics, there are two stages of niobium mineralization events in this deposit: firstly, the formation of primary columbite group minerals, Nb- rich biotite and rutile in magmatic stage; secondly, niobium migrates from magma and primary Nb- bearing minerals to form secondary niobium- containing oxides under late hydrothermal action.