The Beiya gold-polymetallic deposit is one of the typical deposits related to Cenozoic alkali-rich porphyry along the Jingsha River-Ailaoshan-Red river fault system in western Yunnan Province. This presents measurements on the trace elements of fluid inclusions and S-Pb isotopes of ores, and discusses the characteristics of ore-forming fluids and the material sources of ore formation. The results show that the total REE abundance is relatively low, with a range from 5. 19 to 9. 0×10-6, whilst LREE/HREE and (La/Yb)N reflecting fraction between LREE and HREE vary from 4.121 to 11.249 and from 9.563 to 17.651, respectively. The distribution patterns of REE display a LREE-enriched trend, which is roughly consistent with that of alkali-rich porphyries. The δ34S values are in the range of -2. 4~4. 5‰ and the 208Pb/204Pb, 207Pb/204Pb and 206Pb/204Pb values range from 38.256 to 39.0394, from 15.457 to 15.703, and from 18. 380 to 18. 673, respectively.