Objectives：The Pojiao section is located at the junction of Yangtze platform and Youjiang basin in Anlong county, Guizhou Province. Because of its special paleogeographic position, the research of the Pojiao section is useful for the comparison among Anlong area, Luoping Biota and Panxian Fauna in paleoecologcial environment and regional stratigraphy. It can help to build the stratigraphic framework. Methods: The main methods of this investigation are surveying section and conodont biostratigraphy in detail. At the same time, we study regional correlation of the strata in the southwestern margin of the Yangtze platform. Results: A group of conodonts were discovered in the Pojiao section, belonging to middle and upper part of the Xinyuan formation. Besides few ramiform elements, most elements are classified into the Genus Neogondolella. Four conodont zones have been established from bottom to top: Neogondolella bulgarica Zone， Neogondolella bifurcata Zone， Negondolella constricta Zone and Neogondolella constricta cornuta Zone (the top undefined). According to lithologic character, we divided the section into third parts. It was composed of sandy mudstone, limestone and calcirudite. Conclusions: The Xinyuan Formation in Pojia section is a platform- margin slope facies stratum of Middle Triassic. The appearance of conodonts indicate that the strata of this period was close to but not enter the Latinian period, belonging to the mid- and late- Anisian. This research has important significance for exploring basin evolution in this period.