By analyzing the new ammonites from the Wayao Member of the Upper Triassic Falang Formation, this study aims to ascertain the age of deposition and elucidate the underlying factors responsible for lithological changes in the Falang Formation.Methods:A total of five ammonite fossil specimens were collected in this study, all of which were stored in the Geological Museum of Guizhou Province (No. GMG20220705001~GMG20220705005). GMG20220705001 is preserved stereoscopically, while the rest are preserved squashed. GMG20220705002~GMG20220705005 contain 40 ammonites, and nine individuals can be identified. Specimens were repaired using a pneumatic pen and sand blasting machine. Measurements of the specimens were taken using vernier calipers with an accuracy of 0.1 mm. Fossil images were captured using a SONY ILCE- 7M3 SLR camera with an FE 24- 105 mm f/4 GOSS lens. The post- processing of the images was conducted using CorelDRAW 2018 and Adobe Photoshop CS software tools. The measured shell parameters included shell diameter (D), umbilical diameter (U), and height of the last ring (H). For squish- preserved specimens, the width of the ring was not measured.Results:The specimens GMG20220705001~GMG20220705003 are attributed to the Arctosirenites mingqingensis sp. nov. The A. mingqingensis sp. nov. is characterized by the fine and dense ribs. Some other pointed specimens are attributed to the Klipsteinia cf. radiata and Trachyceras multituberculatum.Conclusion: ① Three genera and three species of ammnoid were described, including a new species Arctosirenites mingqingensis sp. nov., as well as the Klipsteinia cf. radiata and Trachyceras multituberculatum; ② based on ammonite biostratigraphy, the lower boundary of the Wayao Member of the Falang Formation in Guanling area of Guizhou is assigned to be Julian 1 (early stage of the Early Carneian ), while the upper layers is approximately Tuvalian 1 (early stage of Late Carneian ); ③ based on regional structure analysis, lithology examination and biostratigraphic data, the lithological variations between the Zhuganpo Member and the Wanyao Member of the Falang Formation are attributed to structural factors rather than CPE events.