Reshui molybdenum polymetallic deposit is a porphyry deposit newly discovered in the east of the East Kunlun Orogenic belt in Qinghai Province. The molybdenum deposit is mainly divided into four ore belts, ore bodies have a variety of shapes,such as strip,vein. Rock alteration have characteristics of Planar distribution, linear array.In order to determine the metallogenic age of this deposit,we have carried out measurements to Re-Os isotopic dating on molybdenites collected 6 samples from the the body,yielding the model age between 229.4±3.1Ma and 230.6±3.1Ma,the age distribution is concentrated,and the results give an isochron age of 228.6±7.9Ma, MSWD=0.25,with an average 230.2±2.5Ma, MSWD=0.025, this dicates that the mineralization in the Reshui molybdenum polymetallic deposit formed in Indosinian.The 6 molybdenite samples of Re contents vary from 13.02×10-6to 17.7 ×10-6indicating that the oreforming material is crustmantle mixed.Combining with the existing metallogenic age shows that indosinian metallogenic events are more significant in orogenic belt of East Kunlun,and magmatic hydrothermal deposit with larger metallogenic potential after the collision stage.