Abstract: The sub-complete skeleton of a new basal iguanodontoid, Bolong yixianensis gen. et sp. nov., was discovered in the Yixian Formation of Western Liaoning Province, China. This new taxon is characterized by several cranial and dental autapomorphies:a depressed area at the junction between maxilla and lachrymal, the caudal ramus of prefrontal forming a rostrocaudally depressed area above the orbital margin, the ventral process running caudally parallel to the ventral margin of the predentary, the rostrodorsal articular surface for the predentary occupying less than two-thirds of the height of the dentary and the rostral tip of dentary therefore situated above the ventral third of the bone, and the primary ridge deflected distally on maxillary crowns. It differs from Jinzhousaurus, also from the Yixian Fm of Western Liaoning by at least 14 cranial and dental characters, including the not-down-turned rostral tip in its maxilla, bifurcate ventral process in predentary, with several secondary ridges on maxillary teeth, etc. Bolong is one of the most basal iguanodontoids ever discovered in Asia.