Abstract: The Shijia gold deposit is a quartz−vein type gold deposit located in the north of the Penglai−Qixia gold belt in Jiaodong. The mineralization process of Shijia can be roughly divided into quartz−pyrite−sericite (I), quartz−polymetallic sulfide−gold (II) and quartz−calcite−fluorite (III) stages. The rare earth element (REE) and trace elements of pyrite coexisting with natural gold in the quartz−polymetallic sulfide−gold stage was analyzed by inductively coupled plasma mass spectrometry (ICP−MS) to discuss the properties of ore−forming fluids in the Shijia gold deposit. Results show that pyrite is relatively enriched in sulphophile elements such as Cu, Pb, Zn, and mainly occurs in pyrite in the form of mineral inclusions. The contents of REE in pyrite are relatively low, enriched in LREE, and depleted in HREE, with ΣREE, LREE/HREE values and (La/Yb)_N values of 2.55×10⁻⁶～20.94×10⁻⁶, 16.15～52.12 and of 18.26～481.62, respectively. Pyrite shows significant negative Eu anomalies (δEu=0.16～0.62) but no obvious Ce anomalies (δCe=0.89～1.33), and Hf/Sm, Th/La, Na/La ratios are all less than 1. Combined with previous studies of fluid inclusions, it is indicating that pyrite is precipitated from a reducing fluid dominated by Cl−enriched under the mechanism of fluid immiscibility. The wide variation range of Y/Ho, Zr/Hf, and Nb/Ta ratios suggests that the hydrothermal system was disturbed during the mineralization process, which may be related to the addition of meteoric water. The contents of Co and Ni and the Co/Ni values indicate that the pyrite is of hydrothermal origin, and the ore−forming fluids are presumed to be similar to the metamorphic fluid which may be associated with the devolatilization of the enriched lithospheric mantle.