Abstract: Based on a national project of surveying and evaluation, Pb-polymetallic deposits including Ruocuo were discovered in the Pb-Zn mineral belt in the southern margin of Gangdese, Tibet.The LA-ICP-MS zircon U-Pb isotopic dating result of diorite closely related to the mineralization of Ruocuo deposit is (55.01 ± 0.88) Ma, indicating that this ore spot was formed in the early Himalayan period, rather than in the late Yanshan period defined by the predecessors. And it may also belong to a large-scale metallogenic event of the Pb-Zn ore belt in the northern margin of Gangdese.It is proven that the mineralizing conditions in the Pb-polymetallic ore belt in the southern margin of Gangdese is similar to which in the northern margin, and the diagenetic/metallogenic ages of the metallogenic rock of these belts both belong to the early Himalayan period and also belong to the mass Pb-Zn diagenesis in Gangdese; the prospecting potential of hydrothermal vein type and skarn type and crypto-explosive breccia type in this ore belt is huge. And also, the discovery of those Pb-polymetallic deposits including Ruocuo and the establishment of the Pb-polymetallic ore belt in the Southern margin of Gangdese pointed out new directions for the prospecting in the Gangdese mineralizing belt, Tibet.