Objectives: Yaojialing Zn—Au polymetallic deposit is a special large sized Zn—Au deposit, Tongling, Anhui province, which is newly discovered in China in recent years. This paper describes the basic geology characteristics of the ore deposit,and using Re Os isotopic dating by molybdenite. The results showed that, Yaojialing molybdenite model ages is 140.3±2.0 ~ 143.0±2.2 Ma, the weighted average age is 141.43±0.85Ma, MSWD = 0.78, the isochron age is 142.5 ± 1.6Ma, MSWD = 1.2. It shows that Yaojialing Zn—Au polymetallic deposit was formed in the late Early Cretaceous, and it consistent with Tongling district of other metal deposits in diagenetic mineralization age. The samples of w(Re) is between 0.2421‰～1.346‰, it indicated the minerals is from mantle derived magma. The deposit was formed in the first phase of mineralization of the Yanshan diagenesis and mineralization in the Yangtze River and is in the stage of regional tectonic motives of conversion in the eastern of China.