Abstract: This paper reposts a thalattosaur specimen collected from the Late Triassic Xiaowa Formation in Xiaoxingan Village, Luxi County, Yunnan Province.It is the first record of Thalattosauria fossil outside Guanling, Guizhou Province.The specimen consists of 9 well preserved dorsal vertebrae, 21 dorsal ribs, and several gastralia.4 dorsal vertebrae are present and arranged as a sequence of natu-ral order.The length of dorsal vertebrae is about 12cm.The transverse process is well developed.The two ends of the dorsal verte-brae are slightly biconcave, distinctly different from ichthyosauria vertebrae with obvious biconcave.The specimen is tentatively as-signed to the Thalattosauria.The new discovery provides new information for paleobiographic distribution of the Thalattosauria and the search for new fossil localities of the Guangling biota.