Abstract: The REE characteristics of different carbonate rock types were studied based on petrologic analyses of carbonate rocks from the Buqu Formation in ancient oil pools in the southern Qiangtang Basin. The carbonate rocks in the study area were classified into limestones, clay-dolomicrites, (residual) grain dolostones, crystalline dolo-stones and saddle dolomites. All kinds of carbonate rocks have a low REE content (∑REE), and some of the saddle dolomite samples have a higher ∑REE than limestones, indicating the mixing of outside liquids. Different carbonate rocks have different REE contents, but their distribution patterns are similar due to the standardization of surface waters of the Pacific Ocean. The La_N/Yb_N ratio averages 2.86, with a slight light rare earth concentration and a heavy rare earth loss. Light rare earth concentration degree decreases with the increase of dolomitization. The positive δCe anomaly (average 2.94) and positive δEu anomaly (average 1.43) showed that the Buqu carbonate rocks were deposited in an oxic environment. Dolomitization fluids mainly came from oceanic formation water in the same period. The diagenetic environment changed to reductive after hydrocarbon charging. At the end of Early Cretaceous, the Lhasa and Qiangtang blocks shear collided, helping atmospheric fresh water enter the Buqu Formation. Affected by the Cenozoic tectonic thermal event again, saddle dolomites were formed. Tectonic thermal events provided temperature conditions for Eu²⁺ concentration.