Abstract: This paper presents U-Pb zircon geochronology, petrology, and major and trace elements of Cretaceous felsite porphyry veins in western Fuzhou basin, Fujian Province. These data were used to investigate the genetic relationship between felsite porphyry and Fuzhou composite granite body. Felsite porphyry shows purplish gray color and is mainly composed of orthoclase phenocrysts, and the well-developed flow structure is present on the margin. Felsite porphyry veins have a NE-trending strike and intruded into Fuzhou composite granite body. Felsite porphyry shows the features of calc-alkali and I-type granites, with the emplacement age being 97.4Ma; it was formed in the transition period between early Fuzhou composite granite body (111~100Ma) and late Fuzhou composite granite body (95~90Ma). The geochemical characteristics between the above three phase rock types present a graduallychanged transitional relation on the time scale. That is, this felsite porphyry is the product of the tectonic regimes conversion between Early and Late Cretaceous in southeastern China. The authors thus hold that the transformation age may be 97Ma.