The Nanling region in South China is characterized by intense multi-period granitic magmatism，and the granites generally are enriched in heat-producing elements （HPEs）.It is vital to study the geochemical behavior of HPEs in tectono-magmatic evolution，which is rarely discussed in depth.A dataset of geochemistry and geochronology on Mesozoic granites covering the Nanling and coastal regions is collected in this study，to analyze HPE geochemistry in fractional crystallization of different type granites，then to evaluate the variations of granite radioactive heat production （RHP）in geological evolution.Triassic and Jurassic granites are exposed in Nanling region，while Cretaceous granites are mainly distributed in the coastal area to the east of Nanling region.In terms of the genetic types，the Triassic granites basically belong to S-type and A-type granites，while the Jurassic and Cretaceous granites are I-type and A-type，and part of Triassic S-type granites and Jurassic-Cretaceous I-type and A-type granites are highly fractionated granite.In sharp contrast，taking 5 μW/m3 as the threshold value of high RHP，S-type and A-type granites with high fractionation belong to high RHP rocks，and the vast majority of I-type granites belong to high RHP rock in Nanling region，while the coastal granites do not have the feature of high RHP.The study has shown that different source rocks restrict the geochemical behavior of HPEs in granitic magma evolution.From the perspective of different periods of granites，the contents of U and Th also vary from magmatic evolution.In general，the fractionated degree （Rb/Sr）of Triassic granites is obviously lower than that of Yanshanian （Jurassic and Cretaceous）granites in Nanling region，among which，Jurassic granites have the highest fractionated value，and the Th and U contents are relatively richer.It is also found that tectonic settings of the granites affect Th and U contents.Correspondingly，the Mesozoic granites formed in different tectonic settings have discrepant