The Jiudian large-size gold deposit occurs as quartz veins in the footwall of the ZhaoPing Fault, and belongs to the southern section of the ZhaoPing metallogenic belt in Jiaodong Peninsula, eastern China. This study presents new fluid inclusion, geochemical, stable isotopic, and mineralogical data that provide insights into the sources of the ore metals, the temperature of mineralization, and the nature of the fluids involved in four different ore-forming stages. Cathodoluminescence imaging indicates four stages of quartz: the early-stage euhedral quartz that unrelates to mineralization and contains small-size fluid inclusions (Qz-1), the quartz containing abundant fluid inclusions and coexisting with pyrite (Qz-2 and Qz-3), and the late-stage quartz occurring as sulfide-barren veinlets crosscutting previous veins or mineral assemblages (Qz-4). Fluid inclusions include three types: H₂O–CO₂ ± CH₄ (Type 1), two-phase aqueous inclusions (Type 2), and liquid aqueous inclusions (type 3). Fluid inclusions in Qz-1 are dominated by type 1, but in Qz-4 are only type 3; whilst Qz-2 and Qz-3 contain all three types fluid inclusions. Type 1 inclusions comprise three phases (liquid H₂O + liquid CO₂ + vapor CO₂), with two carbonic phase ratios cluster at 10 %–30 % and 60 %–90 %. Type 2 inclusions also comprise two types, with vapor/liquid ratios focusing at 10 %–40 % and 60 %–80 %, respectively. All the fluid inclusions have homogenization temperatures of 198.5–329.2 °C, salinities of 3.95–12.39 wt% NaCl equivalent, and densities of 0.72–0.96 g/cm³. The quartz of main mineralization stages recorded the highest salinity, although the density of the fluids did not change markedly over time. These fluid inclusion data indicate that the Jiudian deposit has been formed from a mesothermal fluid system enriched in CO₂ and CH₄, and genetically belongs to the orogenic-type. The C, H, O and Pb isotopic data indicate that the ore-forming metals and fluids were mainly sourced from Precambrian metamorphic basement and Mesozoic granites, with a small contribution from the mantle. This suggests that the Early Precambrian host-rocks significantly contributed metals to the ore-forming system. Therefore, a new genetic model for the Jiudian gold deposit is proposed to incorporate the Early Precambrian basement, Mesozoic intrusive rocks and ZhaoPing fault system.