Located in the northeast margin of Qiangtang terrane between Jinshajiang suture zone and Bangonghu-Nujiang suture zone, the Dongmozhazhua and Mohailaheng Pb-Zn deposits in Yushu area of Qinghai Province are typical Pb-Zn deposits in the Cu-Pb-Zn polymetallic mineralization belt within the northern part of the Nujiang-Lancangjiang-Jinshajiang area. Although these Pb-Zn deposits are in the front belt of Yushu thrust nappe system, the connection between Pb-Zn ore deposits and thrust nappe system remain unclear. Field investigations show that calcite is milk white in color, macrocrystalline, irregular and sack-like in form and is intersected by late mineralization. It was formed during the transitional stage from the compression stage (thrust nappe stage) to the extension stage (mineralization stage) and can be regarded as the link between Pb-Zn ore deposits and the thrust nappe system. Formation ages of the transitional stage in the Dongmozhazhua and Mohailaheng ore districts, determined by both Rb-Sr and Sm-Nd isochron methods for calcite, are 35.2～35.5 Ma with an average of 35.4 Ma and 34.0～34.6 Ma with an average of 34.3 Ma, respectively. Formation ages of such a transitional stage are synchronous with Pb-Zn mineralization epoch (35 Ma and 33 Ma, respectively). In combination with regional mineralization geological setting, the authors established a tentative tectonic model for metallogeny of the Pb-Zn deposits from the thrust nappe stage to the mineralization stage in Yushu area, i.e., India-Asian collision led to the lifting of the orogenic belt relative to the Tertiary foreland basins in the northern margins of the Qinghai-Tibetan plateau, and strong compression resulted in the thrusting of these basins (37～40 Ma). During the transitional stage from the compression stage to the extension stage (34～35 Ma), the mixing of early orogenic fluid and basin fluid resulted in the formation of macrocrystalline calcite. At last, fluids generated from the orogen migrated laterally along gently-dipping detachment faults of the thrust systems toward the basins and evolved into Pb-Zn ore-forming fluids through the interaction with country rocks and the mixture of early orogenic fluid. The ore-forming fluids migrated vertically along major thrust faults and finally accumulated in the back thrust induced by thrust-nappe structures at shallow levels to form Pb-Zn ore deposits.