Abstract: This paper presents 14 whole rock lead-lead isotopic compositions，contents of U, Th and Pb and hence the calibrated Pb isotopic composition of Mesozoic volcano-intrusive rocks from the northern margin of Dabieshan Mt．These rocks have relatively high 204Pb(1.371-1.439％, averaging 1.411％), low206Pb/204Pb ratios(15.975-17.363, averaging 16.713), slightly varied 207Pb/204Pb ratios(15.305-15.537, averaging 15.422)and varied 208Pb/204Pb ratios(36.856-38.816, averaging 37.500). It suggests that these rocks were derived from a source of low μ values which was mainly related to the basement metamorphic rocks with obvious U loss during intermediate to high grade metamorphism. Comparative studies with published regional lead isotopic data show that they are to a great extent similar to the feldspar- lead isotopic composition of the Mesozoic granitoids from Dabie Block within Dabie-Jiaonan subprovince and generally have the lead isotopic characteristics of North China plate. In view of rock series of the research region, we found that, except basaltic andesite from Shangcheng, the shoshonitic series have the highest content of 204Pb and the lowest ratios of Pb isotopes (204Pb= l.438-1.439, 206Pb/204Pb=15.975-16.010, 207Pb/204Pb= 15.349-15.442 and 208Pb/204Pb =36.873-36.931); the alkaline series have the lowest content of 204Pb and the highest ratios of Pb isotopes(204Pb=1.385-1.387, 206P/204Pb= 17.308- 17.363, 207Pb/204Pb= 15.494-15.537and 208Pb/204Pb= 37.984-38.088); while the high-potassium cale-alkaline series have the intermediate content and ratios (204Pb= 1.415-1.427, 206Pb/204Pb= 16.385-16.621, 207Pb/204Pb= 15.305-15.435 and 208Pb/204Pb= 36.965-37.487). These indicate that the source of these three different rock series re quite different in forming age and nature. Compared with those of the other samples,the basaltic andesite samples from Shangcheng, Henan Province were of abnormal lead isotopic compositions(204Pb= 1.371, 206Pb/204Pb= 17.307-17.315, 207Pb/204Pb= 15.405-15.419 and 208Pb/204Pb= 38.738 -38.816).It can be inferred that the source was of distinct Th-enrichment character.