The Gufang-Yangying area in the southeast of Fengning Manchu Autonomous County, Hebei Province, is located at the northern margin of the North China Craton, tectonically situated at the junction between the northern margin uplift belt of the North China Craton and the Chengde North Basin of the Yanshan-Liaoxi rift zone, adjacent to the Shangyi-Longhua regional fault. The area is dominated by metamorphic rock series of the Neoarchean Upper Chongli Group (Yangying and Aijiagou formations), with complex structures, well-developed folds, and iron deposits primarily consisting of sedimentary-metamorphic iron ore and ultra-poor magnetite, generally positioned along northeast-trending tight synclinal structures. Although previous geophysical surveys have been conducted, large-scale high-precision ground magnetic measurements remain insufficient, resulting in inadequate delineation of three-dimensional deep ore body structures and constraining deep prospecting efforts. This study, based on 1∶5000 high-precision ground magnetic survey data, employs reduction to pole, variable-height upward continuation, field separation, analytical signal, vertical derivative, and tilt derivative processing, combined with rock physical property statistics, and utilizes the open-source SimPEG framework for three-dimensional magnetic susceptibility inversion to reveal the spatial distribution characteristics of magnetic bodies within a 1 km depth range; rock physical properties indicate significant magnetic contrast between mineralized iron-bearing rocks and host rocks, providing a robust foundation for magnetic exploration. Inversion results show that magnetic bodies are distributed in a northeast-southwest trending strip-like pattern, mainly concentrated in the central-eastern and southwestern parts, highly consistent with known surface ore bodies and the Upper Chongli Group metamorphic series; vertically, they exhibit scattered distribution in shallow depths, concentrated and continuous in middle depths, and rapid weakening in deeper levels, with three-dimensional displays at different susceptibility thresholds further confirming that high-susceptibility zones are predominantly in the central-eastern part, forming large lens-shaped bodies that partially extend close to the surface, reflecting progressive thickening and enlargement of ore bodies along dip directions. The study confirms that sedimentary-metamorphic iron deposits in the area are controlled by Neoarchean regional metamorphism, conforming to the typical BIF-type metallogenic model at the northern margin of the North China Craton; high-precision three-dimensional susceptibility inversion effectively addresses the knowledge gap in deep structures under complex geological conditions, providing high-resolution geophysical evidence for precise localization of concealed ore bodies, with the central-eastern high-susceptibility zone representing the most favorable target for deep prospecting and warranting priority for drilling verification. These findings deepen understanding of deep metallogenic elements in the study area and offer reliable technical approaches and integrated geological-geophysical methodologies for deep prediction in similar sedimentary-metamorphic iron ore districts along the northern margin of the North China Craton.