Abstract: Kecun granite porphyry is located in the western part of Jiuhuashan National Geopark and in the west side of Jiuhuashan granite. Study of LA-ICP-MS zircon U-Pb dating indicates that granite porphyry emplaced at 125.8±0.9 Ma, close to the intrusion age of Jiuhuashan granite, suggesting that it should be the product of early Cretaceous magmatic activity. The Kecun granite porphyry is enriched in SiO₂, total alkalis and incompatible elements, depleted in Ba, Sr and Ti, and has high 10 000×Ga/Al values and zircon saturation temperature. All of these features are similar to geochemical characteristics of A-type granite, indicating that the Kecun granite porphyry was formed in an extensional tectonic setting. This study can conclude that the tectonic environment of southern Anhui Province might have transformed from early compression to extensional tectonic settings at ca. 125 Ma.