Abstract:Lushui antimony deposit in Northwest Yunnan is a newly discovered ore spot. Its host rock is a set of primary mylonite, it is a fault-controlled deposit. In order to determine the genetic types of the Lushui antimony deposit, H-O-S isotopes of quartz and sulphide ore were studied. Combined with the field orebody formation, the study area can be divided into two stages of metallogenesis, ① In the early age, the ore body hasSimpregnated structure, and born in the mylonite foliation, ② in the main ore-forming period, the ore body is vein-like, associated with quartz vein which is perpendicular to Mylonite schist direction. The δ D value of quartz is between -95.4 ‰ and 88.8 ‰, and δ18OH2O value is mainly between -10.25 ‰ and 9.75 ‰. In the diagram of δD VS. δ18OH2O, the projection point of H-O isotope mainly falls near the precipitation line. The δ34S value of pyrite is about 4.1‰ ~ 4.9‰, the δ34S value of stibnite sample is about 1.2 ‰~1.3 ‰ and the total sulfur value is 2.23 ‰, which is characterized by deep magmatic sulfur. The age of diagenesis and metamorphism are 42 Ma and 38 Ma, respectively. The tectonic control of stibnite and quartz vein in the study area is obvious, indicating that the metallogenic age should be less than 38 Ma. The antimony deposits in and around the Xishan Qinghai-Tibet Plateau are mostly related to the porphyry. The existence of the porphyry in the vicinity of the study area, combined with its H-O-S isotopic characteristics, the author judges that the Lushui antimony ore may have undergone two metallogenic events, which are related to the porphyry in the early stage. The retrofit of atmospheric precipitation was received in the later period.