A few fresh graphite samples including a small amount of marble surrounding rock were taken from several large scale crystalline graphite mining areas in the north of Huangling basement dome for ore petrographic and geochemical analysis, and the source of ore-forming materials was discussed through corresponding analyses and diagrams. The graphite ore in this area occurs in a set of khondalite series of Huanglianghe Formation (Pt₁h), and the main ore types are graphite schist and graphite gneiss. According to the analyses of major and trace elements and carbon isotopes, the recovered ore protolith was a set of carbonaceous (sand) argillaceous sedimentary rocks, and the graphite carbon almost came from organic matter rather than from inorganic carbon in marble. According to the element composition and paleogeological evidence of the deposit, it is inferred that the source area of the Huanglianghe Formation was mainly Yemadong Formation (Ar₂y, tholeiitic), followed by Dongchonghe gneissic complex (Ar₂D, granitic), rather than the single "granitic rock as the source area" as previously thought. During the conversion process from the supply source to the ore-forming parent rock, strong geochemical changes took place rather than simple mechanical transfer of materials.