The writers have studied the Pb isotopic composition of quartz in hydrothermal quartz veins in the Zoige uranium deposit, and regard Pb isotopic ratios of quartz as a bridge linking up the Pb isotopic of the composition parent rocks with that of ores to determine the source of U. The results indicate that the Pb isotopic composition of the quartz in the deposit has a relationship of linear evolution with the Pb isotopic compositions of U-bearing pyrite and intermediate-acid tectono-magmatic granite. So the writers advance a new view that U in hydrothermal ore solutions was derived from intermediate-acid tectonomagmatic rocks rather than stratigraphic rocks, and propose the possibility of using the Pb isotopic composition of hydrothermal quartz to distinguish the sources of ore elements of non-radioactive deposits.