Abstract: In 1983, Dong & Tang (1983) described material of two partial skeletons of an ornithopod collected from the dinosaurian bone quarry at Dashanpu, Zigong, Sichuan Province and coined the name Xiaosaurus dashazpensis. After that, He & Cai (1983, 1984) described two well-preserved skeletons of another ornithopod and denominated them as Yandusaurus multidens. In 1984 in the course of digging the foundation of the building of the Zigong Dinosaur Museum, a nearly complete skeleton of a small ornithopod was collected. It was briefly (lescribed by Peng (1990) and named as Agilisaurus louderbacki. Because this skeleton is So far among the most complete one known in China, or even in the world, it is significant in studying the evolution, paleobiogeography and functional morphology of the ornithopods, so a detailed study of it has been carried out.