Abstract：Granites and related dikes in the Bengbu area have been dated precisely by using the 40Ar-39Ar dating technique. The results indicate that there occurred Precambrian magmatism but also Mesozoic magmatism on the southeastern margin of the North China Ｂlock in the Bengbu area. According to the age data available, the Mesozoic magmatism in the area is divided into the early Yanshanian and late Yanshanian phases and five stages. A chronological framework of Late Mesozoic magmatism has been preliminarily established.