No. HF-3 airborne radioactive anomaly near Qagan Nur Township in Inner Mongolia is situated at the transitional zone between Sonid uplift in Erlian basin and Tengger depression. The outcrop of the anomaly belongs to Neogene Hannuoba Formation. Re-exposing by the shallow borehole reveals that the shallow uranium mineralization of this anomaly is characterized by multi-layering, continuation, stableness and epigenetic re-enrichment, suggesting a complex genesis. This study has basically detected the control factors and formation conditions of the mineralization, thus deepening the understanding of this anomaly.