The authors present a continuous 78 m thick Dongshanding Paleo-lake sediment section based mainly on clayey siltstone and siltstone, which is situated at Jinggou township Dongshanding village (35°35’N, 103°04’E, an elevation of 2 429.5 m). The result of the identification showed that 91% samples pollen amount attained statistical standard among them. According to variation characteristics of spore-pollen assemblage, Dongshanding Formation (Dongshanding Paleo-lake sediment) into 3 spore-pollen assemblage zones (consisting of 6 subzones) can be divided, representing 3 vegetational evolution periods or arid-wet-arid climate change sequence during Early Pleistocene.