Detrital zircon ages of Jianshan Formation H4 quartz sandstone of Bayan Obo Group record two major tectonic-magmatic events in the northern margin of the North Chian Craton (NCC). One Group of age concentrates in the Late Archean—Early Paleoproterozoic (2379~2596 Ma), and the other in the medium Paleoproterozoic (1761~1946 Ma). The results are consistent with the zircon ages of basement rocks in the Bayan Obo region. The 207Pb-206Pb isochron age (1649±45 Ma) of the sedimentary carbonate rocks of the Bayan Obo Group may represent its deposition times. The Pb isotope compositions of ore-bearing dolomite marble are quite different from those of the sedimentary carbonate rocks of the Bayan Obo Group. In the Pb isotope composition and tectonic diagram, the ore-bearing dolomite marbles are concentrated near the mantle evolution line and close to depleted mantle end member \[(206Pb/204Pb)i=15.04~16.49, (207Pb/204Pb)i=15.17~15.28, (208Pb/204Pb)i=31.20~36.40 \], but the sedimentary carbonate rocks are distributed near the orogenic evolution line and close to the pelagic sediment end member \[(206Pb/204Pb)i=17.28~19.35, (207Pb/204Pb)i=15.47~15.69, (208Pb/204Pb)i=36.62~37.12 \].