Abstract: The Tiegelongnan porphyry-epithermal Cu（Au） deposit is one of the most important deposits in the Bangongco–Nujiang metallogenic belt, where pyrite is extensively developed. In this study, trace elements, rare earth elements（REE）, and S isotopes of pyrite were analyzed. Three types of pyrite were identified according to their occurrence characteristics: pyrite-1 and pyrite-2 were related to epithermal mineralization, and pyrite-3 was related to porphyry mineralization. Pyrite-1 had the lowest Au, Ag, Cu, Pb, Zn, and Bi concentrations, whereas pyrite-2 had the highest Au, Ag, Cu, Pb, Zn, and Bi concentrations. The correlations between Cu and Ni, Ag and Cu, Cu and Pb, Ag and Pb, and Pb and Zn could be used to distinguish pyrite-2 from pyrite-3. The δ34S value for pyrite-1（1.9‰） was the highest among the three types. The δ34S values for pyrite-2 and pyrite-3 were between –4.5‰ and 0.3‰, respectively. Pyrite was rich in LREE and depleted HREE and hada “right tilt” pattern in REE distribution. The REE differentiation of pyrite in the shallow deposits（200–450 m） was relatively large with a positive Eu anomaly, whereas the REE differentiation of pyrite in deeper deposits（700–1000 m） was small with a negative Eu anomaly. The migration direction of the sulfur-containing hydrothermal solution in the Tiegelongnan deposit was horizontal from ZK1604 towards the East and vertical from 230–250 m at ZK1604 to the deep and lateral. The high concentrations of Cu, Au, and Ag in pyrite and the positive correlations between Ag and Cu, Pb and Zn, Cu and Pb, and Ag and Pb were important indicators of epithermal mineralization, whereas the negative correlation between Cu and Ni in pyrite indicated porphyry mineralization.