Taking Qiongdongnan Basin as the research object, 7 key sections that can control the basin's tectonic pattern are selected from west to east to restore the balanced profile by using 2D Module of Move software. The extension distances, extension rates and extension velocities of these 7 sections in different periods are calculated. On this basis, the tectonic evolution process and its regional differences in the Qiongdongnan Basin are quantitatively studied. The results show that: (1) the Qiongdongnan Basin has been in a continuous extension process since Cenozoic, and an extension peak appeared during 36 to 28.4 Ma (deposition period of Yacheng Formation), and the extension rate reached the highest value during 36 to 23 Ma (Oligocene), which indicates that the fault activity is the most intense in Oligocene, and Oligocene is the main extension period of the basin; (2) from 23 Ma to the present, the extension rate and extension velocity have shown a gradual decreasing trend, and the extension of the basin has gradually weakened.