Dinosaurs from the Lower Cretaceous Xinminpu Group of the Gongpoquan Basin in the Jiuquan area, Gansu Province, northwestern China were mainly excavated during the course of two projects: the Sino-Japanese Silk Road Dinosaur Expedition in 1992, and the Sino-American Mazongshan Dinosaur Project during 1997~2000. A diverse dinosaur assemblage, including members of Theropoda, Sauropoda, Iguanodontoidea, and Neoceratopsia, has since been discovered. This Gongpoquan dinosaur assemblage is characterized by the coexistence of basal representatives of the diverse clades that would subsequently dominate the Late Cretaceous dinosaur faunas, such as two basal neoceratopsians Archaeoceratops oshimai and Auroraceratops rugosus, the basal hadrosauroid Equijubus normani, and the basal titanosauriform Gobititan shenzhouensis. This assemblage is also characterized by members of the Ornithomimosauria and Therizinosauroidea with unusually large body size (for this geological time interval). Comparative study shows, although closely related, all dinosaurs from the Xinminpu Group in the Gongpoquan Basin are more derived than those from the Jehol Group in the western Liaoning Province in their respectively clades. Considering the younger age of the dinosaur-bearing Xinminpu Group (Albian) in the Gongpoquan Basin than the Jehol Group in western Liaoning Province (late Hauterivian-early Aptian), the Gongpoquan dinosaur assemblage probably represents a later, more derived stage in the evolution of Early Cretaceous Psittacosaurus-fauna in northern China.