The Huayangchuan uranium- niobium polymetallic deposit which is located on the southern margin of the North China Craton, is a large carbonatite- related uranium deposit.Based on detailed field geological work, this paper focus on the petrography, mineral chemistry and chronology of the uranium minerals, using field emission scanning electron microscopy (FE- SEM) combined with energy Disperse spectrum (EDS) and electron microprobe analysis (EMPA). The results show that primary uranium mineral is betafite, followed by uraninite. Uraninite chemical U- Th- Pb geochronology and mineralogical evidences provide the timing constraints and insights into the formation of the Huayangchuan uranium- niobium deposit. Two types of mineralization are identified and documented here: magmatic uranites and betafites related to (aegirine- augite) biotite calcite carbonatitic and syenite pegmatitic veins, formed during the peak (~201 Ma) associated with a large number of altered betafites, and high- temperature vein- hosted uraninites and betafites related to granitic gneiss, formed during the peak (~129 Ma) with few unaltered betafite grains. Minerology and mineral chemistry study indicate that the uraninite and betafite formed at the late stage may precipitate from the Yanshanian magmatic hydrothermal fluid which leached the uranium element from the early betafites. It is demonstrated that the early uranium mineralization related to the (Aegirine- augite) biotite calcite carbonatitic veins, is the primary stage for the deposit, while the late uranium mineralization may be only the altered produced due to the Yanshanian magmatic activity. In summary, the Huayangchuan uranium- niobium deposit show the genetic relationship with the Indosinian- Yanshanian carbonatitic veins but superimposed by the Yanshanian magmatism activity.