Based on an incom plete skeleton with a skull，a new genus and species of Simoedosauridae，Liaoxisauruschaoyangensis is erected． Liaoxisaurus comes from the Early Cretaceous Jiufotang Formation of westernLiaoning．It is distinguished from other derived Choristodera in that the short mandibular symphysis，less than20 % the length of the lower law，and the nearly square tooth alveolus．Liaoxisaurus has a relatively shortrostrum，which occupies 49．8 %of the whole skull length．