1. The 8th Institute of Geology & Mineral Exploration of Shandong Province, Rizhao 276826, Shandong, China;
2. NLR Key Laboratory of Metallogeny and Mineral Assessment, Beijing 100037, China;
3. Institute of Mineral Resources, China Academy of Geological Sciences, Beijing 100037, China

In order to identify the formation time of Reshui Cu-Mo deposit, six molybdenite samples from outcrops and core were used for Re-Os isotopic analysis. The dating results showed that Re content ranges from (5.969±0.042)×10^-6~(15.55±0.11)×10^-6, model ages is (233.1±3.1~235.6±3.1)Ma, the weighted average age is (234.2±1.3) Ma (MSWD=0.40), the isochron age is (234.2±2.8) Ma (MSWD=1.09).The data revealed that the metallogenic epoch was early Late Triassic. Combined with regional geology, geochemistry and isotopic geochronology data, the authors suggested that the Reshui Cu-Mo deposit was formed in a post-collisional background of east Kunlun Orogen during Mid-Late Triassic. There existed a widely occurred magmatic-tectonic mineralization event during Triassic in east Kunlun, from Qimantage in the west to Ngola in the east.