The Yaguila Pb-Zn-Ag deposit is a large-size ore deposit on the north margin of Gangdise. Some experts considered that the ore deposit was formed by marine jet flow superimposed by magmatism, whereas others thought that it was formed only by magmatism. Detailed drill hole investigations into the Yaguila ore deposit show that both the light brown porphyry and the gray quartz porphyry contain a large volume of ore-bearing stockwork quartz veins. Meanwhile, large amounts of massive ores are developed along the contact zone between the two types of porphyries and limestone. Therefore, both the light brown porphyry and the gray porphyry must have played an important role in mineralization of the Yaguila ore deposit. In the present study, the authors analyzed zircon U-Pb ages for the two kinds of porphyries by using LA-ICP-MS. Mean ages of the concor- dant points for the two types of porphyries are 132.1±1 Ma and 62.4±0.6 Ma, respectively. Typical sedimentary ore bodies were not found during the field survey, but large volumes of skarn ores were found in most ore bodies, indicating that metals of the Yaguila Pb-Zn-Ag deposit were most likely derived from magmatic hydrothermal fluids related to both the light-brown porphyry and the gray porphyry. Therefore, two stages of magma events were found in this ore deposit. The first magma event occurred in the early Cretaceous, related to the light-brown porphyry, which was superimposed by the second mineralization event related to the gray porphyry in the Paleocene. Combined with the results of previous researchers, the authors hold that the ore-forming process dominated by Pb-Zn-Ag mineralization on the north margin of the Gangdise belt occurred during Cretaceous-Miocene period. Intense Pb-Zn-Ag mineralization implies that the paleo-basement of northern Gangdise belt might have played an important role in controlling the metal types of the mineralization in this area.